Talk:Time zone

From Wikipedia, the free encyclopedia
Jump to: navigation, search
WikiProject Time (Rated C-class, High-importance)
WikiProject icon This article is within the scope of WikiProject Time, a collaborative effort to improve the coverage of Time on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
C-Class article C  This article has been rated as C-Class on the project's quality scale.
 High  This article has been rated as High-importance on the project's importance scale.
Wikipedia CD Selection
WikiProject icon Time zone is included in the Wikipedia CD Selection, see Time zone at Schools Wikipedia. Please maintain high quality standards; if you are an established editor your last version in the article history may be used so please don't leave the article with unresolved issues, and make an extra effort to include free images, because non-free images cannot be used on the DVDs.


Newer Map?[edit]

This map is already out of date. Sri Lanka for instance is now no longer 6 hours ahead of UTC. —Preceding unsigned comment added by (talk) 00:30, 14 August 2006

Yeah, it even says that some time zones have changed. Is it so hard to make a new map? --The monkeyhate 19:57, 5 February 2007 (UTC)
If somebody can compile a list of changes required, I may have the time to do it. The map was made at the end of 2005. But I will be pain in the ass asking questions about DST rule on obscure places. --ChoChoPK (球球PK) (talk | contrib) 21:13, 5 February 2007 (UTC)
There is an SVG version of the 2007 World Factbook Time zone map here. It should be easier to edit than a raster PNG or GIF etc.--Trounce 16:34, 22 February 2007 (UTC)
There are a few errors on the map.
  • Taiwan is not named, yet East Sahara is.
  • Sea of Japan is not correct.
Marasama (talk) 19:17, 16 March 2009 (UTC)

The time zone of Ukraine is also incorrect on this new map. It is correct on the old map. I had wrote about this in the discussion of the new map, but nobody changed this. --D.M. from Ukraine (talk) 21:47, 10 December 2011 (UTC)

Where the Nautical TimeZones Are[edit]

One thing that isn't always clear to people looking at the timezone map -- the nautical time zones do not start at 0, 15, 30, 45, 60, degrees, etc. The Greenwich time zone runs from 7.5°W to 7.5°E, so successive nautical time zones are at 22.5, 37.5, 52.5, 67.5, 82.5, 97.5, 112.5, 127.5, 142.5, 157.5, 172.5 both to the East and West of the Greenwich Prime meridian. Before the use of GPS was common, any mariner who got confused on this point could get confused about where the ship was, since celestial navigation depends on knowing the time. So I added a couple of lines to the discussion of Nautical Time Zones. --SV Resolution(Talk) 18:34, 24 August 2006 (UTC)

Japanese text?[edit]

Just a minor edit, but in the history section, there was some Japanese text that really didn't belong (although I don't know what it means, the article is in English, anyway). If anyone can translate it, then put it back and just disregard this comment.

This hodgepodge ended when Standard zone time was formally adopted by the U.S. Congress on 19 March 1918. いやな事ばかり Time zones were first proposed for the entire world by Canada's Sir Sandford Fleming in 1876 as an appendage to the single 24-hour clock he proposed for the entire world (located at the center of the Earth and not linked to any surface meridian!).

Thanks, Torpov 03:20, 5 September 2006 (UTC)

That text was added by an anonymous editor ( on 2 September 2006 and only partially reverted by Malrase. Thanks for completing the reversion. — Joe Kress 02:22, 6 September 2006 (UTC)

Politically correct Map?[edit]

Interesting how the map wishes to be politically correct by listing who claims what territory, does this really belong on a timezone map? Imho it belongs on a political map. If we are going for such niceties, then I'd suggest that the bounderies of Tibet (pre-occupation) are also added. After all the country was invaded and is still illegally occupied by a foreign army. No-one recognizes the annexation. As a matter of fact the legal government in exile of Tibet may have set another time zone (I suspect they would not be using Beijing time). So the legal time zone and de facto occupation time zone may be different. —Preceding unsigned comment added by (talk)

The map is an extension of the CIA map "Standard Time Zones of the World" (pdf, 680KB). Obviously, the CIA thought that those remarks did belong on a time zone map. Because the CIA map is the basis of the Wikipedia map, all borders are those officially recognized by the United States. The CIA map is one of the few that is in the public domain and hence does not have any copyright restriction. Most maps are copyrighted and hence are forbidden on Wikipedia. Anyone is welcome to create their own map, but it must be their own creation with no copyright or be in the public domain. You cannot take a copyrighted map and simply add the boundaries of Tibet to it—that would violate the original copyright. Before the creation of the People's Republic of China in 1949, most of Tibet was in the GMT+6 time zone along with parts of Sinkiang, Tsinghai, Sikang, and Outer Mongolia under the nominal control of the Republic of China (using Wade-Giles romanizaton). See Time in China. — Joe Kress 16:25, 12 September 2006 (UTC)

Before Time Zones[edit]

I think the article could be more clear about how local time operated before time zones came into use. In the United States, for instance, was everyone on the same time prior? If not, how were local times established? Sylvain1972 12:24, 15 October 2006 (UTC)

Yes, the last two paragraphs of the introduction could be worded better. Originally, every city had a different time, the time displayed on a sundial (corrected for the equation of time). Thus with hundreds of cities, the United States alone could have had hundreds of times except that cities north-south of each other had the same time. — Joe Kress 06:46, 16 October 2006 (UTC)

Quick question...[edit]

What is the abbrieviation for the zone Wikipedia's servers are in? I can't remember whether it is California or Florida and I can't for the life of me find it. Lady BlahDeBlah 17:44, 28 October 2006 (UTC)

According to Wikipedia, its main servers are in Tampa, Florida, with additional servers in Amsterdam and Seoul. The statement in History of Wikipedia#Beginnings of a new project that its server (singular?!) is in San Diego, California, appears to be historical. — Joe Kress 07:19, 30 October 2006 (UTC)


DUT is refered to in the article, but it is not defined/explained. David Broadfoot 13:51, 9 November 2006 (UTC)

It may not be defined, but it is linked. Click on the link for the definition. The definition is a bit too complex to include here for such a minor portion of the article. — Joe Kress 21:01, 9 November 2006 (UTC)

External link removed[edit]

  • - Animated time zones - Shows the relationship between arbitrary time zones and "natural" zones.

I removed this non-commercial external link because the page required Flash and because the content seemed unintuitive. I understand that it's showing each of the timezones in black and each of the "natural" time zones in gray but that wasn't very obvious. Of the three links that I removed, it was the only one that seemed that it might be useful. ~a (usertalkcontribs) 15:25, 20 December 2006 (UTC)

exteranal links[edit]

I've added the link wich was removed by Arichnad. It's a usefull link for a website on the topic of the article, it features quality content which could not be recreated at wikipedia pages, and it is useful for useres who are looking for the time zones invormation. —The preceding unsigned comment was added by Oleksiy.n (talkcontribs) 12:27, 22 December 2006 (UTC).

Sorry for the late response Oleksiy. In the past I've removed the two links to: and I won't remove them again until I get other editors to agree that they fail WP:EL. Please weigh in. ~a (usertalkcontribs) 05:27, 27 December 2006 (UTC)
I think these (and a few of the others) should be removed per WP:EL. Grouse 16:53, 28 December 2006 (UTC)

WikiProject CCT[edit]

hear ey! Hear ey! The WikiProject CCT is now open for new recruits. If you are interest in Current City Time please give us a visit at WP:CCT. --CyclePat 00:03, 14 January 2007 (UTC)

UTC± Notation[edit]

If the notation for a time range five hours ahead of UTC is UTC+5, then shouldn't the notation for five hours behind be UTC−5, not UTC-5? It seems like it should be a minus, not a hyphen, for consistency. 20:04, 14 February 2007 (UTC)

I agree that we should use a minus sign, except that UTC-5 has the minus sign, while UTC−5 has a hyphen. --ChoChoPK (球球PK) (talk | contrib) 05:04, 15 February 2007 (UTC)
The hyphenated negative forms, like UTC-5, were created when special characters, like the minus sign, were not allowed in article titles by Wikipedia software. But now that special characters are allowed, the "proper" form UTC−5 is allowed. I noted that a few minus versions did not have redirects to their hyphenated articles, so I created those redirects. (The anonymous editor did use the correct signs.) — Joe Kress 06:55, 15 February 2007 (UTC)

1st country to celebrate New Years[edit]

I was watching The Weakest Link and Anne said that some town in New Zealand celebrated new years 1st. But looking at the time zone map, it seems that there are quite a few places that actually see the New Year in before NZ. Can anyone offer any explanations? --nocturnal omnivorous canine 12:17, 3 March 2007 (UTC)

This kind of TV show is usually not very rigorous on details like this. Nor are the maps on the complimentary magazines found on many airlines. --ChoChoPK (球球PK) (talk | contrib) 23:22, 3 March 2007 (UTC)
Actually New Zealand is one of the first, but not the first. The Line Islands in Kiribati has time zone UTC+14 and celebrates new year first. But it has only 8000 inhabitans and introduced this time zone in 1995, and many tables and maps have not been updated. Actually our map in this article is wrong too. The Chatham Islands has UTC+13¾ in December and 600 inhabitants and comes after the Line Islands.
New Zealand has UTC+13 in December (and UTC+12 in July) and is one of the first. Tonga celebrates new year at the same time as NZ. Only the Line Islands and Chatham Islandsare before. Many maps and tables do not include daylight saving time info, becasue it would make it more complicated. But the entire NZ (and Tonga) has new year at the same time, because it is based on official time. So Gisborne is not earlier than the rest of New Zealand. -- BIL (talk) 12:29, 22 February 2008 (UTC)


The map was recently changed from Image:Timezones_optimized.png to Image:2007-02-21 time zones-white.png. The first map was based from a 2005 edition of the CIA map, with the necessary corrections according to the content of Wikipedia. Now it's 2007, the first map is somewhat out of date, such as Sri Lanka, but the second map, CIA's 2007 edition not only continues to have the errors carried from 2005, it has not made the necessary updates to reflect recent changes. So I reverted. --ChoChoPK (球球PK) (talk | contrib) 02:13, 1 April 2007 (UTC) Someone replaced the 2005 map with CIA's outdated version again. I made an updated version of the map which reflects all changes made and scheduled up to June 2008, and included it in the article. I did not include DST information on the map as the 2005 version did, perhaps I will do that later. I have noticed that it is almost impossible to find an updated world map of time zones, commonly found maps are usually very old. CIA's 2007 map, for example, still shows Sudan in UTC+2, but it moved to UTC+3 in 2000. Dave (talk) 20:50, 28 May 2008 (UTC)

I reccomend that you at least change the CIA date at the lower right from 3-05. You might also change the other code numbers at the lower right to something else indicative of your update. — Joe Kress (talk) 02:19, 29 May 2008 (UTC)

The most recent and clearest map of time zones that I have found is from HM Nautical Almanac Office at I suggest that the map in the article be replaced with that one.

Alexselkirk1704 (talk) 01:58, 2 March 2009 (UTC)

Linux is Unix-like, not Unix based.[edit]

In paragraph Unix, it says that "Most Unix based systems, including Linux and Mac OS X, keep system time as UTC (Coordinated Universal Time)." Though Linux is Unix-like, not unix based. "Linux (IPA pronunciation: /ˈlɪnʊks/) is a Unix-like computer operating system family." [[1]] "A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification."[[2]] --Natasha2006 12:27, 10 April 2007 (UTC)

50 hours[edit]

Because the earliest and latest time zones are 26 hours apart, any given calendar date exists at some point on the globe for 50 hours. For example, 11 April begins in time zone UTC+14 at 10:00 UTC 10 April, and ends in time zone UTC-12 at 12:00 UTC 12 April.

Could someone please explain what the author(s) of the above are trying to say? Do they mean "When it's 10:00 UTC 10 April in time zone UTC+14, it's already 11 April somewhere else in the world, and when it's 12:00 UTC 12 April in time zone UTC-12, it's still 11 April somewhere else in the world"? The way it's currently written, it seems to be saying that 11 April begins on 10 April and ends on 12 April - which confuses the hell out of my brain. -- JackofOz 01:27, 6 June 2007 (UTC)
What you said is correct. The first place to get April 11 is the time zone of UTC+14. This means at UTC time it is 14 hours earlier, 10 AM the day before. Now the last place to change from April 11 to April 12 is UTC zone -12. Which is 12 hours laster than UTC (12 noon). All it means is, if you travel to the right places fast enough, because of the time zones you could technically spend up to 50 hours with the single date of April 11 - a jet lag of some 26 hours!--Dacium 02:37, 6 November 2007 (UTC)

Blatant Error[edit]

As described above, there is a glaring faux pas in this article. "April 11 begins in time zone UTC+14 at 10:00 UTC April 10, and ends in time zone UTC-12 at 12:00 UTC April 12." WRONG!! If the time is 04/11 00:00 at UTC-12, then the time at UTC+0 is 12 hours later, obviously at 04/11 12:00, not 36 hours later as the article would have me believe. Miqrogroove 00:01, 27 June 2007 (UTC)

In time zone UTC-12, 4/11 ends at 0:00 4/12 local time (the first second of 4/12). So that very time point is 12:00 UTC April 12. The statement in the article is not wrong. --ChoChoPK (球球PK) (talk | contrib) 00:42, 27 June 2007 (UTC)
I will grant you that point, however the existing article doesn't make sense. I recommend saying "April 11 begins in time zone UTC+13 at 11:00 UTC April 10, and April 12 begins in time zone UTC-12 at 12:00 UTC April 12."
Furthermore, I would like to point out the UTC+14 timezone does not appear anywhere on the updated CIA map. This article may be stale. —Preceding unsigned comment added by Miqrogroove (talkcontribs) 00:56, 27 June 2007
I believe the original intent is "A local April 11 can span 50 hours globally". Regarding UTC+14, I believe Kiribati changed its time zone so that they were the first to enter the third millennium. The article Kiribati says so. The CIA map is known to be inaccurate. --ChoChoPK (球球PK) (talk | contrib) 01:18, 27 June 2007 (UTC)
The third millennium began 6.5 years ago. Perhaps they switched again? Miqrogroove 02:11, 27 June 2007 (UTC)
According to the comments in the most recent zoneinfo file for Kiribati, that nation changed it time zones so that the entire country has a uniform date as of 1995-01-01. This created the UTC+14 time zone, and as far as I can tell, Kikibati hasn't made any subsequent changes to its time zones. The zone info comment cites the Wall Street Journal, page 1, 1996-01-22. Scott Roy Atwood (talk) 03:17, 22 February 2008 (UTC)

DST nonsense[edit]

removed: The tendency to draw time zone boundaries far to the west of their meridians allows greater utilization of more daylight in the afternoon hours. - The use of daylight is INDEPENDET of clock time! TimeXCode 20:52, 1 September 2007 (UTC)

Its not indepedant. Most countries have fixed work hours (9am to 5pm for example), moving the zone boundaries west and establishing it on that point creates more daylight after work has completed. By your logic everyone should just use UTC no matter where they are because day/night time is indepedant of clock time...--Dacium 02:33, 6 November 2007 (UTC)


IST is not calculated at Mumbai, Maharashtra, it is calculated at Allahabad, Mirzapur Uttar Pradesh. --Rsrikanth05 (talk) 11:42, 18 November 2007 (UTC)

What is the world's last time zone?[edit]

Would anybody be nice enough to tell me what is the world's last time zone? I would really like to know what it is. Thanks. Best wishes, Albert —Preceding unsigned comment added by Albert Cheng (talkcontribs) 21:26, 6 December 2007 (UTC)

I assume you are asking what is the time zone with the greatest westward offset from GMT time. According to the article, GMT-12 is the last time zone, but uninhabited Baker Island and Howland Island are the the only landmasses there. According to the 2007g version of zoneinfo, GMT-11 is the westernmost inhabited timezone, and it is shared by Midway Island, Niue, American Samoa, and Samoa. Scott Roy Atwood (talk) 20:09, 19 February 2008 (UTC)
Albert may also mean the most recently added time zone. That would be UTC–4:30 added on December 30, 2007 by and for Venezuela. But because we are answering his query late, the next most recent was UTC+14 created by Kiribati for its Line Islands in the central Pacific by skipping December 31, 1994. Not counted are boundary shifts of previously existing time zones and Daylight saving time. — Joe Kress (talk) 01:01, 21 February 2008 (UTC)

Useful time zone table?[edit]

Does anyone have any use for this table? I made it, but I don't have any use for it now. - LA @ 07:40, 18 February 2008 (UTC)

New South Wales and Java[edit]

In the section on Java, there is a paragraph that talks about problems caused by time zone changes introduced by New South Wales for the 2000 Olympics. It is not at all clear from the context what exactly the problem is, or what relevance it has to Java. Did it cause all time zones in Java to change there DST start/end dates? Was the problem that OS and Java time zone defintitions would be out of sync? And if so, wouldn't that be the case any time anybody changes time zone definitions, which happens very frequently? What is special out that particular time zone change? I'm strongly inclined to remove that entire paragraph, because it doesn't appear to add any value to the page. Please let me know if you disagree. Scott Roy Atwood (talk) 20:51, 27 March 2008 (UTC)

Scope of this Article[edit]

I came to this article wanting to know where the boundary between Eastern Time and Central Time is, not because I wanted to know how SmallTalk handles time. I'm thinking that moving all of the computer timezone handling information to a separate article would probably make sense, and having detailed time zone maps in this article, and or table(s) with links to the articles about the individual time zones, would probably improve this article. JNW2 (talk) 16:49, 16 April 2008 (UTC)

I suspect the computer time zone info should probably remain here, but I have no strong opinion on that. Much of your request for details on individual time zones is a result of splitting off List of time zones from this article. Your requested links are in that article. I'm adding a dab link at the head of the article to cover requests such as yours. — Joe Kress (talk) 21:02, 16 April 2008 (UTC)

Time zones at the poles?[edit]

I came to this page looking for information about the treatment of time zones at the poles, but didn't find a satisfactory answer. There is a little bit about conventions in Antarctica, but one the web there seem to be claims that it generally uses UTC+0. Does this give scientists any troubles? Are there accounts of explorers moving from time zone to time zone with single steps? ---Jake (talk) 23:22, 25 April 2008 (UTC)

The research base at the South pole use New Zealand time, like the McMurdo base. The supplies to the South pole usually comes from New Zealand. The research bases on the Antarctic peninsula usually have Chilean or Argentinian time zone. The rest use varying time zones. This info was listed in List of time zones. The North pole has no official time zone, since it is at sea and has no longitude. Visiting ships and planes usually use the time zone of their departure port/airport. --BIL (talk) 20:49, 26 April 2008 (UTC)
Defined Time zone boundaries in the far North and far South run along lines of longitude. Therefore, the Poles are in many Time Zones (not all, because Norway at +1 meets Russia at +3, cutting off +2; and the Afghan Zone has entirely land borders with other Zones, for example). The offset from GMT/UTC used at and near the Poles is another matter; that's up to the residents. So is the area, perhaps circular, to which that offset applies. That is, unless thare has been a formal agreement to have a Polar Zone of a particular extent and offset. Note that the whole of the UK land surface is in Zone GMT+0; but an enclave within it uses UTC+1. (talk) 19:33, 15 February 2009 (UTC)

Database of timezone boundaries?[edit]

Anyone care to post a link to some kind of table/database that maps longitude/latitude coordinates to time zones? For finding what timezone a place is in? E.G. something like <Latitude> <Longitude> <Timezone> for each latitude(rounded down to 1 decimal point?)? And then it would be selected by something like select Timezone from Table where Latitude=round(LocationLatitude,1) order by abs(Longitude-LocationLongitude) limit 1 ?? Thanks in advance :) this is very important since just doing round(LocationLongitude/15) is useless thanks to the timezone boundaries being completely warped by political territories and stuff. —Preceding unsigned comment added by (talkcontribs)

I know of no such database. It would be very difficult to construct, especially near the time zone boundary, because zones within multi-zone countries are specified by the political subdivisions of the country, which can be natural features like rivers or mountain ranges or even surveyed lines. For an example of this complexity see the definition of the boundary between the central and mountain time zones of the United States in 49CFR71.7 (T means township and R means range, the borders of survey townships E-W or N-S of a specific surveyed point). — Joe Kress (talk) 19:16, 4 June 2008 (UTC)

time zone (disambiguation)[edit]

it doesn't exist, but anyway appears at top of page... i tinhk it must be deleted —Preceding unsigned comment added by Alfalo (talkcontribs) 22:18, 15 July 2008 (UTC)

Ummm.... it does exist Cheers --Pak21 (talk) 15:53, 14 October 2008 (UTC)

More images and See also links[edit]

This page contains useful informations. But some more images about time zone can be attached. I think under the h2-heading See also more links should be added. --Amit Gomes (talk)

Articles on time zones and time offsets[edit]

I've tried to open a discussion about the pages for individual time zones and time offsets at Talk:List of time zones#Articles on time zones and time offsets. Your input there would be much appreciated! - IMSoP (talk) 01:47, 26 October 2008 (UTC)

Population by timezone[edit]

There should be a table of world population by time zone. Is -0900 the least populous time zone, etc. Jidanni (talk) 17:24, 20 January 2009 (UTC)

Such a table would be very difficult to compile and maintain. We cannot just add the populations of countries or their political subdivisions because many time zone boundaries cut through the smallest political subdivisions, even through quite a few rural United States counties. I suspect that even a few small cities are cut, although US law specifies that municipalities on a time zone boundary are in one or the other (laws in other countries may not do so). For example, US 49CFR71.7 states: "All municipalities located upon the [US central-mountain] zone boundary line described in this section are in the mountain standard time zone, except Murdo, S. Dak., which is in the central standard time zone." I can state that the time zone with the least population is UTC−12, which has no permanent population. — Joe Kress (talk) 19:22, 20 January 2009 (UTC)

Perhaps just use a simple Geographic information system overlay of world time zones upon a world population layer. Jidanni (talk) 21:01, 20 January 2009 (UTC)

I made a table of population by time zone, based on the most recent population estimates available. I used official data from each country for 2008-2010 whenever possible, otherwise I used population estimates from the United Nations. Particularly difficult was the Democratic Republic of the Congo, because it has a high population growth rate and recent estimates are not available for every province. As Joe Kress mentioned above, in the United States and Canada there are many small subdivisions that are split into different time zones, but these countries release very detailed population estimates almost every year, so I could find all the information needed.

I have references to support all the numbers, but to add the references I would have to show the complete version of the table (it has about 500 rows), detailing the population by country and subdivision in each time zone, and it may be too long to include in the article. Should the short version below be included, even without references? Dave (talk) 10:34, 15 April 2010 (UTC)

Time zone Population
UTC+8 1,533,702,989
UTC+5:30 1,199,223,000
UTC+1 719,233,391
UTC+2 489,081,883
UTC+3 452,580,526
UTC+7 367,499,893
UTC-5 283,223,936
UTC+5 234,354,234
UTC 232,711,011
UTC-3 223,965,587
UTC-6 223,608,992
UTC+9 210,416,127
UTC+6 193,750,864
UTC+3:30 74,196,000
UTC-4 65,370,196
UTC-8 57,930,888
UTC+6:30 50,020,628
UTC-7 34,244,943
UTC+5:45 29,331,000
UTC+10 29,272,990
UTC-4:30 28,722,657
UTC+4:30 28,150,000
UTC+4 26,170,830
UTC+12 5,398,014
UTC+9:30 1,875,354
UTC+11 1,757,856
UTC-10 1,571,049
UTC-1 763,288
UTC-9 699,403
UTC-3:30 487,463
UTC-11 247,560
UTC+13 104,041
UTC+14 8,809
UTC-9:30 8,632
UTC-2 3,138
UTC+11:30 2,141
UTC+12:45 650
UTC+10:30 347
UTC+8:45 150
UTC-12 0

Time Zones are Static[edit]

The Article should be revised to correct the usage of Time Zone. Time Zones do not change seasonally (consult dictionaries; don't rely on Wikipedia). (talk) 18:50, 3 May 2009 (UTC)

Exclusion of a Small But Official Time Zone[edit]

In this article, there is no mention of GMT-3.5, which encompasses the island of Newfoundland on the east coast of Canada. (talk) 03:42, 17 July 2009 (UTC)

It is in List of time zones at UTC-3:30, P†. — Joe Kress (talk) 08:31, 17 July 2009 (UTC)

Recent refs[edit]

I removed one reference recently added by Smithcraft36 because it is wrong and mostly discusses a clock not built until long after time zones were adopted. Its major error is the modern spokeman's opinion that "The New York Central Railroad knew it couldn't run the system back then without time zones, ... so they petitioned Congress." No railroad would have accepted time zones if they were not forced to do so by many calls for time zones from non-railroad writers. The railroads did not petition Congress for time zones. Rather, the railroads were afraid that Congress would dictate time zones which the railroads would not like so they prempted it and adopted their own time zones. These zones were amenable to railroads because the time zone boundaries ran through railroad terminals in major cities so that an entire length of track could keep the same time. But these zones were detrimental to the cities containing those terminals because each of those major cities now had two times differing by one hour, requiring them to chose one or to continue keeping local solar mean time.

I moved the other reference but left it in the article due to its historical interest even though it also had an error. It says that Britain established a standard time in 1828. That is an apparent typo because Great Britain's railroads did not adopt a standard time until 1848. — Joe Kress (talk) 21:34, 16 September 2009 (UTC)

Livingstone County?[edit]

The following appeared in the article as of 02:10, 8 September 2009, by user

There are also a few unorthodox time zone changes such as the 15 minute time difference in Bragg, Newfoundland (Maritime Standard Time) MRST and the 8 minute time difference for Livingstone County, Alberta (Prairie Standard Time PRST).

This didn't make sense to me (an 8 minute time zone difference?), so I started checking. I can't even find mention of a Livingstone County in Alberta, so I deleted that part. If anyone can find a citation of such a time zone, I will stand corrected. Bunthorne (talk) 00:07, 21 September 2009 (UTC)

Global time zone[edit]

Can a small section be included on the ideas of some that only a single (global) timezone is to be used (eg as UT1) ? This suggestion would thus use "the time" only as an indicator eg for planning meetings, ... (which can be an annoyance if you just flew into the country, are having a longe range communication (eg telephone, netmeeting, ...) and no longer as an indicator for the "time of day"; eg where 12h means midday. Instead, everyone at any different time zone will simply adhere to other hours to get up, have lunch, go to bed, ... (talk) 07:37, 31 October 2009 (UTC)

Only if there is some kind of general attention to the idea already. To write a new suggestion in Wikipedia is Original research, a violation of the idea of what to use Wikipedia for.--BIL (talk) 08:53, 10 February 2011 (UTC)

Absurd UTC[edit]

The following paragraph shows the absurdity of the the UTC business (though not of course for scientists-but we are not all physics professors!) It says-"If the notation for a time range 5 hours ahead of UTC is UTC+5 then -etcetc" Now the obvious question a child or a normal person would ask is-But where isthis UTC place? What do we add the 5 hours too? And the answer of course is -we add the 5 hours to the time at Greenwich which is a place in London(yes Iknow the scientificdifferences etc but as I said -we are not all scientists) So why not get rid of all your inferiority complexes about the British and stick to GMT-which is what normal people do and which everyone understands It really is quite extraordinary seeing the time on posts and comments etc on the internet being given in UTC+ or minus.It means nothing-unless you instantly change it to GMT!!! If anyone disagrees with this and the absurdity of using the meaningless term UTC, will they please tell me exactly WHAT I add the 5 hours to in the sentence below? Please tell me WHERE exactly is this mysterious UTC place?

Oh and just to irritate you a bit more-There has in recent years been considerable discussion about where or when the New Year -or millenium etc begins.In fact it doesnt begin in the middle of the Pacific etc It begins at Greenwich London --or on the first stroke of Big Ben and thats official as laid down inthe Washington agrement of 189- Winston1911 (talk) 04:46, 31 December 2009 (UTC)

You may wish to read this article on Coordinated Universal Time (also known as UTC). --Glenn L (talk) 07:39, 31 December 2009 (UTC)

The UTC article is a good one. GMT should be avoided. Not because of any Britishism (pro or con), but because it is ambiguous. See for example for a discussion on all the meanings of GMT. Bsdimp (talk) 22:33, 9 February 2011 (UTC)bsdimp

Actually the current - 2014 - NATO/OTAN definition of 'Zulu Time' explicitly refers to 'Greenwich Mean Time' [3] "zulu time / heure zulu Greenwich Mean Time" — Preceding unsigned comment added by (talk) 14:24, 3 September 2014 (UTC)
Yes, but only UTC is supported by international standards. When official or completely unambiguous usage is needed, UTC is what is necessary. Both Greenwich and Zulu continue in more informal use, and presumably NATO knows what it means when it uses it: "equivalent to UTC", I think. It's just a traditional usage continuation from back when Greenwich was an international standard. Btw, some people are now confusing traditional "Greenwich" with "current time in Greenwich, England", which shifts according to daylight savings time. UTC does not shift. Presumably, NATO does not either. Evensteven (talk) 16:43, 3 September 2014 (UTC)

Improving the lead section[edit]

This page is currently tagged as having an unsatisfactory introduction. Will a short paragraph about the history of time zones (used to be local solar time, later railroad time, bla bla bla) solve the problem? If so, I'm willing to add such a paragraph. If not, feel free to explain how else to improve the lead section. —Preceding unsigned comment added by Skysmurf (talkcontribs) 01:49, 10 January 2010 (UTC)

Inconsistency with other article[edit]

In the additional information section it is stated that both Russia and France have 11 time zones. However, the article Time in Russia states that Russia's 11 time zones are more than any other country in the world. I'd think that one of the two must be wrong and should be edited.

Moreover, according to Time zones by country France has 12 time zones, which is inconsistent with both this page and Time in Russia.Skysmurf (talk) 04:43, 28 January 2010 (UTC)

how does time changes in same zone[edit]

how does time change from ecuador to chile —Preceding unsigned comment added by (talk) 21:56, 17 February 2010 (UTC)


This page must talk about PST EST ect... that's the way we are often presented Timezone. --Transisto (talk) 22:35, 17 March 2010 (UTC)

Is the Eastern Time zone *always* GMT - 0500?[edit]

I see that many mail servers (and computers) in the Eastern Time Zone are currently set to GMT - 0400 (4 hours offset from GMT).

This time-zone article does not mention if it's correct procedure to modify your system's GMT offset to account for (or correct for) DST *or* if your GMT offset is *CONSTANT ALL YEAR* for your geographic location or zone?

WHAT IS THE ANSWER? —Preceding unsigned comment added by (talk) 12:51, 31 March 2010 (UTC)

Eastern STANDARD Time (EST) is GMT-0500, while Eastern DAYLIGHT Time (EDT) is GMT-0400, during which period Daylight Saving Time is in effect, hence the one-hour difference. Whether to make the adjustment or not depends on your computer and mailing system. Most newer computers automatically make the time change, but older ones and smaller mail systems and message boards may not do this for you.--Glenn L (talk) 17:17, 31 March 2010 (UTC)
Eastern Standard Time is an ambiguous term. In Australia, it's UTC+10. There are others. And of course all relate to UTC, not GMT. Groogle (talk) 04:04, 7 February 2011 (UTC)

Time zones are arranged around countries, not cities[edit]

In most parts of the world, with the exception of the United States, and several other very important countries, time zones are for a full country. Listing UTC-04:30 as the time zone for Caracas may be reasonable for an American, but it's absurd for a Venezuelan. Besides, if countries are listed whenever possible, the problem of too many cities in the table is supressed. Esmito (talk) 19:40, 15 April 2010 (UTC)

Most computers use the Olson timezone database (also known as the tz timezone database). This package generally identifies time zones by a combination of a continent name, and the name of the most populous city in a particular time zone. This naming convention was adopted because the names of major cities tend to be more stable than the names or borders of countries. But you are right that most laypeople in most countries would tend to identify their time zone with their country, rather than by a specific city. I would agree that using country names in the table where appropriate might be a better approach. Scott Roy Atwood (talk) 23:52, 16 April 2010 (UTC)
This article was created many years ago with a few sample cities and a comprehensive list of countries within each time zone. Since then, the country list has been was split off into the separate article List of time zones by UTC offset and the city list has been greatly expanded to include many cities within every time zone. The country article also includes a list of cities within each time zone, so the city list in this article is superfluous and should be removed. — Joe Kress (talk) 04:47, 17 April 2010 (UTC)
I suppose Arthur Olson is an American. Any Chilean or Peruvian can tell you that if tomorrow the Peruvian city of Tacna (70°14'54"W) were annexed to Chile, then Tacna (today UTC-5 all year round) would have Chilean time (UTC-4 in the winter and UTC-3 in the summer). On the other hand, if the Chilean city of Arica (70°20'W, 53 km from Tacna) were annexed to Peru, then Arica would have Peruvian time. Now that I think of it, Tacna and Arica once were both Peruvian and once they were both Chilean. It's obvious for me that in those situations they had the same time. Esmito (talk) 20:30, 29 April 2010 (UTC)
The theory behind the Olson time zone database is that it tracks both present and historic time zone changes from 1970 onwards (and even earlier in some cases). In order to do this, it has an separate time zone for every geographic region that has an independent time zone history since 1970 and names each zone based on the most prominent city in that region. That means the Olson notion of time zones doesn't always map directly to the normal notion of time zone. To take one of your hypothetical examples, if Tacna were to be annexed by Chile, the Olson time zone database would create a new time zone named America/Tacna, which would be the same as America/Lima (Peruvian Time) for pre-annexation dates and times and America/Santiago (Chilean Time) for post-annexation dates and times. In this way, a resident of Tacna could set his computer to this time zone and get the correct times for events both pre- and post-annexation. In a country like Argentina, with lots of states with independent time zone histories, the Olson time zone database recognizes 12 distinct time zones, even though the the entire country is all on UTC-03 for most of the year. Scott Roy Atwood (talk) 00:58, 22 February 2012 (UTC)
Let me add that one state having two time zones, such as Oregon or Nevada is not understandable in the rest of the world. Esmito (talk) 20:58, 29 April 2010 (UTC)
Very few countries in the world span enough longitude for multiple times zones to be necessary or desirable. In the United States, several states have a small portion of the state in a different time zone than the bulk of the state. This is usually because that portion the state is relatively isolated from the rest of the state, and the population center in that portion have closer geographic and economic times to the neighboring state and timezone than the state in which they are located. For example, West Wendover, Nevada is contiguous with Wendover, Utah on the Nevada side of the state border. In the case of Alaska, the state simply spans too much longitude for a single time zone to be practical, so the westernmost potions of the Aleutian Islands are in a different time zone. Scott Roy Atwood (talk) 01:10, 22 February 2012 (UTC)

Time zone: region versus offset[edit]

In the current article the concept "time zone" is used in two different and conflicting ways. In the lead it is a "region" on Earth. In later sections it is an "offset from UTC". The conflict arises from the practice of "daylight saving time". For a fixed location, the region stays the same, but the offset changes. In central Europe for example the time zone region is UTC+1, but in summer the time zone offset is (UTC)+2.

Not only in the article is this confusing, but also in the real world. Try using calendar software to coordinate conference calls across time zones, especially when not all parties observe daylight saving time.

The description of this can be found in the article, but is well hidden. The article should be refocused to clarify this unfortunate inconsistency in terminology from the outset.

Woodstone (talk) 06:07, 5 May 2010 (UTC)

I had never even heard of refering to daylight saving time as a different time zone until last year. All of the traditional literature only refers to a time zone region, relegating DST to a one hour shift, not a new time zone. — Joe Kress (talk) 18:57, 5 May 2010 (UTC)

Template: Unwrap?[edit]

In the History section it says "About Template:Unwrap, time signals were first transmitted by telegraph ...". I suspect the Template:Unwrap is supposed to say something else. Dan Sachs (talk) 19:59, 26 May 2010 (UTC)

Should be {{nowrap}}. Done. −Woodstone (talk) 21:19, 26 May 2010 (UTC)

Moved discussion from Main Introduction[edit] The best time zone is that one is Spain not in Namibia, as Gari Wilson-Randalls believes. Actually, according to renowned scientists and world experts, the time zone in Namibia is far superior to that of Spain, contrary to what Mr. Manuel Balkan has previously stated. ... wait a minute... whats that?... we just received official information that Madame Wilson-Randalls has been executed for lying about the time zone, since even Namibians agree that their time zone is far inferior compared to almighty Spaniard time zone. It seems that Mr. Balkan is still using outdated facts. Since their independence, Namibians have denounced the previous erroneous thoughts and asserted that Namibia does in fact have a far superior, if not the best, time zone. Mr. Balkan is said to be on the run from authorities, and any information on his whereabouts should be reported immediately so justice can be served. In other news, Madame Wilson-Randalls is alive and well, and enjoying Namibian hospitality.

-- Glenn L (talk) 18:08, 11 June 2010 (UTC)

endashes for timezones?? Those dashes mean "minus", not "a range"[edit]

If WP:MOSDASH says use endashes, it's wrong. I'll go look... (talk) 06:09, 16 July 2010 (UTC)

GMT vs UTC confusion[edit]

GMT has NOT been redefined to be the same as UTC. The term GMT is at best ambiguous and should be avoided. If you mean mean solar time, you should use UT1. If you mean the time scale that presently ticks at a fixed rate, but has leap seconds added to it to keep it in sync with UT1, you should use UTC. The reference for the redefinition of GMT is likely being misrepresented (I don't have access to a paper copy, so cannot refute it conclusively). The time scales were never harmonized so that the second is the same in both. If it were, there'd be no need to have leap seconds. A mean solar second is just a little bit shorter than a SI second, which is why we have to have a leap second every so often to keep UTC form getting too far ahead of UT1.

The time act in the United Kingdom hasn't been repealed, so officially the UK is on UT1 not UTC. Practically, however, all the government sources of time use UTC.

The main introduction likely should simply skip all the nonsense about this stuff anyway. It should be noted in a separate section that the official time in many countries is still mean solar time, but the de-facto time is all based on UTC. The main introduction should likely read something like:

Time zones of the world are based on the time in Greenwich. They are all a fixed number of minutes offset from this baseline. Most are a fixed number of hours, although there are a few time zones that differ by a fixed number of hours plus 15, 30 and 45 minutes. In some parts of the world, the time zones have been fairly stable for a long time. In other parts of the world they are more fluid. Daylight savings time modifies the base-line time zones, and rules for it are more subject to change.

See for a comprehensive history of GMT and why it isn't the same as UTC. Bsdimp (talk) 22:30, 9 February 2011 (UTC) bsdimp

Time Zones: Established by the free market and railroads.[edit]

To keep trains running on time, connections able to leave on time, and retain a standard that would improve communications and profitability.

Quote; "Although the large railway systems in U.S. and Canada adopted standard time at noon on November 18, 1883, it was many years before such time was actually used by the people themselves. The use of standard time gradually increased because of its obvious practical advantages for communication and travel. Standard time in time zones was established by U.S. law with the Standard Time Act of 1918, enacted on March 19. Congress adopted standard time zones based on those set up by the railroads, and gave the responsibility to make any changes in the time zones to the Interstate Commerce Commission, the only federal transportation regulatory agency at the time. When Congress created the Department of Transportation in 1966, it transferred the responsibility for the time laws to the new department."

[4] (talk) 07:07, 19 March 2011 (UTC)Andrew G. Eggleston Sr.

Time zones were not required "to keep trains running on time, connections able to leave on time". Each railroad was capable of doing that without standard time zones, that is, using its own time even when it differed from the time of other railroads. Their great advantage was to the people who had to get to the terminal in time to meet a specific train, by reducing the multitude of times used by several railroads to only one for each region. Many people were already proposing standard time zones during the 1870s. The only reason railroads adopted time zones in 1883 was to prevent the government from dictating times to them that they might not find advantageous.
"It was many years before such time was actually used by the people themselves" is simply wrong. The article already states "Within one year, 85% of all cities with populations over 10,000, about 200 cities, were using standard time." Detroit was an exception, not the rule. "Congress adopted standard time zones based on those set up by the railroads" is misleadng. The only similarity between Congressional time zones and railroad time zones was that both covered zones and had central meridians based upon Greenwich. Their borders differed drastically. Railroad times changed at terminals within major cities, so technically, cities such as Buffalo, Pittsburg, Atlanta and Charleston were in two time zones. I presume that each of these major cities adopted only one of these zones for their entire area, but have not found any historic statements concerning this. Congressional time zones had boundaries that passed through areas with far fewer people. Nevertheless, junctions are still mentioned within United States law, to wit: "The limits of each zone shall be defined by an order of the Secretary of Transportation, having regard for the convenience of commerce and the existing junction points and division points of common carriers engaged in interstate or foreign commerce." 15 USC 261Joe Kress (talk) 01:47, 20 March 2011 (UTC)

How many major time zones[edit]

The introduction mentions 24 major time zones. Recently somebody changed it to 25 and somebody else changed it back to 24. Assuming that "major" refers to what is basically the nautical time zone system, there really are 25: the offsets 1 to 12 both ways plus UTC itself (the 2 zones at the far end, UTC+12 and UTC-12, are both 7.5 degrees wide instead of 15 degrees like the others). So I'm changing it back to 25.

If "major" in this context really means something else, please enlighten me. --Skysmurf (talk) 20:54, 6 April 2011 (UTC)

As part of my rewrite of the lead, time zones on land are distinguished from nautical time zones. There are 25 nautical time zones and 40 land time zones. Although the 25 land time zones which correspond to nautical time zones could be considered major, that term is no longer used in the lead. — Joe Kress (talk) 05:14, 7 April 2011 (UTC)
Seen. The new lead is a big improvement, thanks! --Skysmurf (talk) 15:49, 7 April 2011 (UTC)
The new lead looks good to me too! --Peter Wisner (talk) 16:42 30 April 2011 {UTC} —Preceding unsigned comment added by (talk) 16:44, 30 April 2011 (UTC)

Island of Great Britain[edit]

Should "island of Great Britain" be "mainland of Great Britain"? There are several "British Isles". --Wikiain (talk) 00:51, 21 May 2011 (UTC)

No. The single "island of Great Britain" is intended, not any of its outlying islands nor the island of Ireland, which was part of the country of Great Britain during the 19th century. British railways connected to London created the first time zone and they could not cross any large expanse of water. A few years later, a separate time zone was created on the island of Ireland by its railroads based on Dublin time, GMT−25 minutes. The 1880 Time Act codified these two time zones, Greenwich mean time and Dublin mean time. — Joe Kress (talk) 03:54, 21 May 2011 (UTC)
Joe, I think I get your point entirely. I happen to be aware of the legal definitional issues, as to what is or has been "Great Britain". However, nobody in the UK refers to "Great Britain" as an "island". So, I still think this might be rephrased. To my mind,"mainland Great Britain" would do the trick. The idea of British railways (or Railways) crossing large expanses of water - or even of land and on time at a reasonable cost to the customer - is intriguing. However, I am tending to read too much in and shall leave this to your well informed judgement. --Wikiain (talk) 12:10, 21 May 2011 (UTC)

India / Pakistan disputed border[edit]

This map needs to be updated in order to reflect current international boundaries. Many people may be updet at the depiction of India's borders.

Please compare current maps, and if at all possible, fix this map. Believe me, if I could I would. — Preceding unsigned comment added by (talk) 00:41, 12 June 2011 (UTC)

Too many solar time articles[edit]

Please see Wikipedia talk:WikiProject Time#Too many solar time articles Jc3s5h (talk) 17:33, 2 August 2011 (UTC)


The list of time zones is not for only countries but for regions as well. For example, region Transnistria in Moldova (or unrecognized country Transnistria - doesn't matter for the issue for time) has own regulation of time. Please do not include the politics aspects while editing. Removing information of the time in these territories desinforms people. (talk) 08:10, 16 October 2011 (UTC)

And this has what to do with too many solar time articles, exactly? Please do include a section header when starting a new topic.
Further: As is clearly stated at the top of the list, it's not meant to be an exhaustive list but rather just mention a few examples. -- Skysmurf  (Talk) 14:51, 16 October 2011 (UTC)
De facto this list is not a list of "a few" examples but a list of almost all countries and territories. (talk) 20:46, 16 October 2011 (UTC)
Insisting that a small region using the same time zone as its neighbouring country is still mentioned separately is the political statement, rather than an attempt to keep the list tidy. -- Skysmurf  (Talk) 14:51, 16 October 2011 (UTC)
The sitation is not as you explained. Transnistria use different with parent state time regulation. (Opposite, for example, to Kosovo that also mentioned in the list but use quite the same time with all neighbouring countries. That is including of Kosovo is the political statement while including of Transnistria is the informational statement). (talk) 20:46, 16 October 2011 (UTC)

No grid on new time zone map[edit]

Why is the grid missing from the latest time zone map? Looks awkward. - Dubfire (talk) 11:19, 7 November 2011 (UTC)

Nation of Samoa[edit]

Is it now (post Dec. 29, 2011) UTC+13, as the text of the map says, or UTC+12? It moved only one time zone, and American Samoa is shown (correctly, I believe) as UTC-11. (talk) 18:45, 31 December 2011 (UTC)

real local sunset time map[edit]

Sorry if this isn't exactly related to article discussion, but it could be incorporated somehow if I am successful, and I imagine several knowlegeable people may follow this page.

I am looking for a map which would show sunset or sunrise times by location on the equinox or solstices. I guess it would be similar to a time zone map, but much more detailed. I suppose it would entail "bands" showing zones in which the sun sets between given times (say between 21h00 and 21h30, 20h30 and 21h00 etc...) at local time. I need it to illustrate the differences in real local sunset times within a time zone. Such a map would be somewhat laborious to create, but i would have thought that there must be something similar out there.

Thanks for any help. Peregrine981 (talk) 11:15, 4 January 2012 (UTC)

Microsoft Windows system time[edit]

The article says, "Windows-based computer systems normally keep system time as local time in a particular time zone." This is flat-out wrong.

If nobody objects I'll try to fix it tomorrow (UTC time). RenniePet (talk) 01:23, 2 March 2012 (UTC)

And while we're at it, the lead says, "Computer operating systems use either UTC or a local time zone to time-stamp events." This is also wrong. It should say something along the lines of UTC being typically used for time-stamping events to avoid various problems that would otherwise exist in systems that span multiple time zones, and to avoid the otherwise incredible ambiguity problem that exists if local time is used in time zones that implement shifts to and from summer time. RenniePet (talk) 01:31, 2 March 2012 (UTC)

Unreferenced fluff in the intro[edit]

Different places on the Earth need to have different clock times because day and night comes at different times around the world. We now use time zones so that people over a wide area can keep to the same time, for simplicity and ease of communication.
Standard time zones could be defined by geometrically subdividing the Earth's spheroid into 24 lunes (wedge-shaped sections), bordered by meridians each 15° of longitude apart. The local time in neighboring zones would differ by one hour, and the variation in the position of the sun from one end of the zone to the other (east vs. west) would be at most 1/24 of the sky. Most of the 25 nautical time zones (specifically UTC-11 to UTC+11) are indeed defined this way, and are 15° of longitude wide. An hourly zone in the central Pacific Ocean is split into two 7.5°-wide zones (UTC±12) by the 180th meridian, part of which coincides with the International Date Line.

If any of this helps get the reader "into" the article, put it back, by all means. But it looks like fluff and speculation to me. The thing about the lunes might go in a history or background section. It's nice to know the relationship between local "ship time" and land time. But I daresay most of our readers are unfamiliar with degrees of longitude and the position of the sun in the sky.

What about the need for everyone to use the same time? Like "work starts at 9:00" or "we work 9:00 to 5:00". If this is more than just a North American or European thing, then let's talk about how people schedule their day and use clocks to do it. Where did the custom of calling midnight 12:00 begin? Why do we use two cycles of 12 hours, rather than one cycle of 24 hours - and where is this still prevalent? Where is railway time (or military time) used, i.e., 3:00 P.M. = 1500 hours? And what parts of these questions should be answered in Time zone? --Uncle Ed (talk) 15:59, 1 May 2012 (UTC)

GMT-12 and GMT+12[edit]

Is there a difference between these two that I'm missing?--Jim in Georgia Contribs Talk 18:39, 29 November 2012 (UTC)

Yes, they will be different dates. For example, right now GMT−12 is 05:00 Friday, November 30, and GMT+12 05:00 Saturday, December 1 Indefatigable (talk) 17:15, 30 November 2012 (UTC)
Thanks.--Jim in Georgia Contribs Talk 20:32, 30 November 2012 (UTC)
Also note that some timezones have UTC offsets beyond 12 hours. For example, the timezones UTC+13:00 and even UTC+14:00 exist. The world isn't "just" divided into 24 time zones, it's more complicated than that. --  Skysmurf  (Talk) 00:43, 1 December 2012 (UTC)

1913 Time Zone Map Discrepancy[edit]

The map shown as a 1913 time-zone map has a dating discrepancy. While the map may have been published in Chicago in 1913, it shows Oklahoma Territory and Indian Territory. Indian Territory was abolished when Oklahoma was admitted to the Union in 1907, so the map is from before that date. It is possible the paper used an old map and drew the time zone lines on it. (talk) 08:18, 25 December 2012 (UTC)

Universal Greeting Time[edit]

Hello. I've added a link to the Universal Greeting Time in the See Also section. I couldn't remember what the acronym for it was, and looked for it here on wikipedia, but was disappointed when i couldn't find it! A friend told me what it was, and since the article exists i thought i'd link it here. I hope it's alright! (talk) 16:19, 22 May 2013 (UTC)

50 hours again[edit]

Because the earliest and latest time zones are 26 hours apart, any given calendar date exists at some point on the globe for 50 hours. For example, 11 April begins in time zone UTC+14 at 10:00 UTC 10 April, and ends in time zone UTC-12 at 12:00 UTC 12 Apr

Hi there, I'm not a native English speaker but isn't that formulation incorrect? My understanding is that "any given calendar date exists at some (selected) point on the globe ALWAYS FOR 24 HOURS" Wouldn't it be more correct to say that "any given calendar date exists on (or when considering) the entire globe for 50 hours." or something like that? Thanks for your thoughts. --Hhgygy (talk) 14:16, 14 June 2013 (UTC)

This is the way I would put it: "Since the earliest and latest time zones are twenty-six hours apart, the time span between the onset of a calendar date in the earliest time zone and the onset of the next calendar date in the latest time zone is fifty hours." In other words: "For fifty consecutive hours, any given calendar date is the current date somewhere in the world."
Another thing that can be said is: "In any given span of 24 hours, there are 22 hours during which two different calendar dates are the current date somewhere in the world, and 2 hours during which three different calendar dates are the current date somewhere in the world."
Also, these things can be said accurately only because neither the earliest nor the latest time zones ever shift for daylight savings. Evensteven (talk) 05:58, 5 September 2014 (UTC)

Unreferenced material[edit]

Article has been tagged for needing sources since 2012. Feel free to reinsert the below material with appropriate references. DonIago (talk) 13:10, 14 May 2014 (UTC)

Relativistic time with Mars rover[edit]

Is there any issue with relativistic time shifts with the Mars rover (e.g. relative motion of Earth antenna and Mars rover antenna)? I'm thinking synchronizing on the nano second scale.--Nowa (talk) 12:35, 17 August 2014 (UTC)

@Nowa, there are always relativistic effects whenever you've got something interplanetary going. What's more, "nano-second scale"? I am absolutely certain that there is not a fixed, linear, or even completely predictable relationship between time measurements or coordinations between Mars and Earth, and, should one be able to take measurements both places at the same instant (if one can even define what "same instant" means), I'm not confident that we could produce a measure to a nano-second degree of accuracy under those conditions. What we could be sure of is at what instant the signal arrives at our location. The time it took to get there? No. Evensteven (talk) 06:06, 5 September 2014 (UTC)

New time zone[edit]

An IP left this message in an article edit. I save it here for reference, and in case anyone is of a mind to investigate and do something about it.

INDIA NOW HAS TWO TIME ZONES..SOME ONE PLEASE CORRECT THIS..Assam state in India got a new time zone..

Thanks. Evensteven (talk) 05:37, 5 September 2014 (UTC)

Planet Earth[edit]!2422&authkey=!AEDdYS3DReTTvEo&ithint=file%2cpdf — Preceding unsigned comment added by (talk) 19:13, 28 January 2015 (UTC)

Daylight Saving Elaboration needed as to why Time Zones are changed[edit]

More Info is needed why the Geographical Time Zones are changed during Daylight Savings instead of keeping the Time Zone and just changing the Time. After all, the countries that change their 'time' during Daylight Saving didn't physically move. ZhuLien (talk) 12:56, 6 April 2015 (UTC) — Preceding unsigned comment added by (talk)

North Korea[edit]

The time zone map now needs to be updated to reflect the recent time zone change of North Korea. Air.light (talk) 17:36, 8 August 2015 (UTC)

External links modified[edit]

Hello fellow Wikipedians,

I have just added archive links to 4 external links on Time zone. Please take a moment to review my edit. If necessary, add {{cbignore}} after the link to keep me from modifying it. Alternatively, you can add {{nobots|deny=InternetArchiveBot}} to keep me off the page altogether. I made the following changes:

When you have finished reviewing my changes, please set the checked parameter below to true to let others know.

Question? Archived sources still need to be checked

Cheers. —cyberbot IITalk to my owner:Online 19:03, 27 August 2015 (UTC)

Unexplained tag[edit]

Tralala0: So you reverted my removal of your tag. Ok, but I will revert you again also unless you justify the presence of the tag. You have only claimed that it is needed. You have not said why, and that's why I reverted you the first time. Evensteven (talk) 00:06, 12 September 2015 (UTC)

The main reason for the reversion is because it removed the citations I added. However, the section also needs additional citations per Wikipedia's verifiability policy, hence the tag. Tralala0 (talk) 00:23, 12 September 2015 (UTC)

It looks like that was my error removing the citation. Sorry for that; don't quite know how that escaped my attention. I still can't see the need for the tag, but I'm going to drop the matter. Evensteven (talk) 06:54, 12 September 2015 (UTC)

Crimea is a part of Ukraine[edit]

But on the standard world time zones map Crimea is separated with border from the other territory of Ukraine. Please fix it. — Preceding unsigned comment added by (talk) 00:51, 9 November 2015 (UTC)

Agreed. Crimea is not internationally recognized as a part of Russia and should not be represented as such. - ILBobby (talk) 01:35, 28 April 2016 (UTC)


The unreferenced statement that "Timekeeping on Mars can be more complex" seems like a judgment an editor made, and is incorrect, in a sense. Local solar time is still used for Mars, without the added complexity of time zones, due to the sparsity of human-related activity there, so in a sense it's simpler than timekeeping on Earth. What's more complex is converting from Earth time to Mars time. It's like saying that the metric system is more complex because centimeters have to be converted to some fractional number of inches -- is there a tag to mark the paragraph as not reflecting an interplanetary view? (talk) 02:02, 9 December 2015 (UTC)

Display issue with wide table[edit]

In the section "Time zone conversions", the collapsible table titled "Time of day by zone" does not display correctly for me – it is too wide, so that the left side is cut off, and there is no horizontal scrollbar. Anyone else have this issue? Is it a bug of the wikitable template? --Florian Blaschke (talk) 16:44, 1 January 2016 (UTC)

The problem in Time zone#Time zone conversions is having style="float:right" in a wide table. It prevents expanding the table to the right with normal scrolling, and expanding to the left works differently. Other right floating content like infoboxes also get problems if the window is too narrow for them. I suggest to simply remove the code. PrimeHunter (talk) 17:16, 1 January 2016 (UTC)
Yes check.svg Done Thank you, it works now. --Florian Blaschke (talk) 21:35, 1 January 2016 (UTC)

External links modified[edit]

Hello fellow Wikipedians,

I have just added archive links to 2 external links on Time zone. Please take a moment to review my edit. If necessary, add {{cbignore}} after the link to keep me from modifying it. Alternatively, you can add {{nobots|deny=InternetArchiveBot}} to keep me off the page altogether. I made the following changes:

When you have finished reviewing my changes, please set the checked parameter below to true to let others know.

Question? Archived sources still need to be checked

Cheers.—cyberbot IITalk to my owner:Online 14:57, 27 February 2016 (UTC)

External links modified[edit]

Hello fellow Wikipedians,

I have just added archive links to one external link on Time zone. Please take a moment to review my edit. If necessary, add {{cbignore}} after the link to keep me from modifying it. Alternatively, you can add {{nobots|deny=InternetArchiveBot}} to keep me off the page altogether. I made the following changes:

When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{Sourcecheck}}).

Question? Archived sources still need to be checked

Cheers.—cyberbot IITalk to my owner:Online 15:51, 22 March 2016 (UTC)

Venezuela to change timezone (May 2016)[edit]

The president just announced a change for VET (Venezuela's timezone) starting May 1, 2016. Details are lacking but most likely is a return to UTC -4. The alleged reason is a measure to reduce electricity usage. [5] More details: Vice-president said that, on May 1st, everyone at 2:30am should advance their clocks half hour. [6] Therefore it is confirmed Venezuela is returning to UTC -4 in 15 days. — Preceding unsigned comment added by Artemis3 (talkcontribs) 17:35, 15 April 2016 (UTC)

+13:00 and +14:00[edit]

This is just stupid!!! There's only 24 hours to use! Who were the dumbs who came out with this bs of +14 hours?? Probably the same kind of morons who think Pluto is not a planet!! — Preceding unsigned comment added by (talkcontribs) 17 May 2016

We have dates also, not only hours. The clocks in zone +13 show two hours more than in zone +11 with the same date by daytime. While clocks in the zone -11 show the same hours as zone +13 but the day before.--BIL (talk) 11:40, 17 May 2016 (UTC)


Sadly Turkey is no more in +2 time zone. Turkey is in +3 time zone. There is no more summer time. --Kirov Airship (talk) 07:11, 8 September 2016 (UTC)

"unexplained removal of historical info"[edit]

@Karl Palmen: well my original idea of that removal of info is that it is less useful to say how many time zone had china used before but more useful to say how many idealized timezone the country extend across. Because if you went onto history there might be many different complex reasons for a country to have many timezones like Japan annexed many countries in WWII which make their country span across a wide area and they just sink back to be a relatively smaller country now (despite most of those place use JST during the occupied period), or alternatively they could have derived their country into various different smaller timezones like Australia in DST. And thus I believe saying it used to use 5 different timezone is not really a descriptive way to describe the situation and thus I have attempted to change that despite it does not appear to work. What do you think about it? C933103 (talk) 12:05, 4 October 2016 (UTC)

I see what you mean and appreciate what you are trying to do, but first you must explain what you mean by idealized time zone and show that there would be five of them. This information does not appear to be present in the Time in China page you link to. Instead, I find the five historical time zones and not all of these are hourly. To make the point, I don't think it is necessary to state the number of time zones and I think for the idealized time zones, one can refer to time zones of normal (15 degrees) width. I'll make a change in line with this. Karl (talk) 11:52, 5 October 2016 (UTC)
@Karl Palmen: The westmost point of China is at 73°E which's UTC+5 in principle, and the eastmost point is either at the west side or the east side of 135° (subject to territorial dispute) which would make it UTC+8/9) and that's what I mean in (4/)5 timezones. (Edit: would it be better to call them nautical time zone?) C933103 (talk) 18:01, 12 October 2016 (UTC)
It looks like four or five nautical time zones would do. Karl (talk) 11:39, 17 October 2016 (UTC)
I like to write that 73°E corresponds to UTC+04:52 and that 135°E corresponds to UTC+09:00 (see also List of extreme points of China), so China would be part of the zones UTC+5 to UTC+9, which are five zones.--BIL (talk) 12:53, 17 October 2016 (UTC)