Friday the 13th

A Friday occurring on the 13th day of any month is considered to be a day of bad luck in English, German and Portuguese-speaking cultures around the globe. Similar superstitions exist in some other traditions. In Greece and Spain, for example, Tuesday the 13th takes the same role. The fear of Friday the 13th is called paraskavedekatriaphobia (a word that is derived from the concatenation of the Greek words Παρασκευή, δεκατρείς, and φοβία, meaning Friday, thirteen, and phobia respectively; alternate spellings include paraskevodekatriaphobia or paraskevidekatriaphobia) or friggatriskaidekaphobia, and is a specialized form of triskaidekaphobia, a phobia (fear) of the number thirteen.

History of Friday the 13th

There is no reliable evidence that Friday the 13th was considered to be especially inauspicious before the late nineteenth century, though both Friday and the number thirteen were separately identified as negative. Because of this, attempts to explain the superstition with reference to historical events are speculative.

One proposed origin relates to the Last Supper. Judas, the thirteenth guest, was instrumental in the Crucifixion of Jesus, which happened on a Friday.

Other theories offered in relation to Friday suggest that Eve offered the apple to Adam on a Friday or the slaying of Abel happened on a Friday (though the Bible does not identify the days of the week when these events occurred).

However, no evidence is known to link the superstition to any specific events or suggest that there is any continuity from the Middle Ages to the present day.

Effects in people and cultures

"It's been estimated that [U.S] $800 or $900 million is lost in business on this day because people will not fly or do business they would normally do,"

Some people are so paralyzed by fear that they are simply unable to get out of bed when Friday the 13th rolls around. The Stress Management Center and Phobia Institute estimates that more than 17 million people are affected by a fear of this day.

A British Medical Journal study has shown that there is a significant increase in traffic related accidents on Friday the 13ths. Despite that representatives for both Delta and Continental Airlines say that their airlines don't suffer from any noticeable drop in travel on those Fridays.

The date is well-known in the motorcycle (biker) community: Since 1981, motorcycle enthusiasts and vendors gather every Friday the 13th in Port Dover, Ontario, Canada. This tradition started on November 13, 1981 by Chris Simons as a gathering of approximately 25 friends. The event has grown substantially, with an estimated 100,000 people attending in August 2004, as well as music bands, vendors, a bike show, etc.

In the Spanish-speaking world, it is Tuesday the 13th (as well as Tuesdays in general) that brings bad luck; a proverb runs En martes, ni te cases ni te embarques (on Tuesday, neither get married nor start a journey).

Occurrence

The following months have a Friday the 13th:

2001	2007		2018		April, July	G
2002		2013	2019	2024	September, December	F, GF
2003	2008	2014		2025	June	E, FE
			2020		March, November	ED
	2009	2015		2026	February, March, November	D
2004					February, August	DC
	2010		2021	2027	August	C
2005	2011	2016	2022		May	B, CB
2000				2028	October	BA
2006		2017	2023		January, October	A
	2012				January, April, July	AG

This sequence, here given for 2001-2028, repeats every 28 years from 1901 to 2099. The months with a Friday the 13th are determined by the Dominical letter (G, F, GF, etc.) of the year. All months whose first day falls on a Sunday will contain a Friday the 13th.

The Gregorian Calendar 400-year cycle contains a whole number (20,871) of weeks and 146,097 days, but the number of months (4800) is not divisible by seven. Along with the 146,000 days, (400 x 365 days), there are ninety-seven February 29's and Leap Year Day's. The easiest way to explain how and why the Gregorian Calendar rotates during any 400-year cycle, there are 365 days every year. Ninety-seven of the 400 years are Leap Year's and contains a February 29, in them, there are 366 days. 365 days is 52 weeks, with one additional day. 366 days is 52 weeks, with two additional days. Just add the additional days, after the fifty-two weeks, during all 400 years. The 97 Leap Year's, doubles to 194. Then add the other 303, the overall total is 497. 97 plus 97 plus 303 equals 497. 497 days equals seventy-one weeks. Add the fifty-two weeks, in the four-hundred year system of the Gregorian Calendar, (other than the 497 additional days), there are 145,600 days, equalling 20,800 weeks. 145,600 days plus 497 days equals 146,097 days, which equals the 20,871 weeks and 146,097 days, listed up above. Because of this, no chosen day of the month up to the 28th can occur the same number of times on each day of the week. The 13th day of the month is slightly more likely to be on a Friday than on any other day of the week.

The distribution of the 13th day of the 4,800 months is as follows:

• 688: Friday (alone).
• 687: Sunday and Wednesday apiece.
• 687 Sundays + 687 Wednesdays = 1,374 months.
• 685: Monday and Tuesday apiece.
• 685 Mondays + 685 Tuesdays = 1,370 months.
• 684: Thursday and Saturday apiece.
• 684 Thursdays + 684 Saturdays = 1,368 months.
• Add the 4 numbers, 688 + 1,374 + 1,370 + 1,368. They total the 4,800 months and equals 400 years altogether.

Every year has at least one month containing Friday the 13th.

Trivia

• Heavy metal band Black Sabbath's first, self-titled album was released in the UK on Friday, February 13, 1970.
• Novelist Daniel Handler, also known as Lemony Snicket, released the 13th book of the Series of Unfortunate Events on Friday, October 13, 2006.
• January 13, 2006, and October 13, 2006, were not only Fridays, but the digits in the month, day, and year of each date add up to 13. This last occurred on October 13, 1520, and will next occur on May 13, 2011.
• There is an almost uncanny occurrence (at least in recent years) of the full moon falling on or very close to a Friday the 13th. July 13th, 1984, February 13th, 1987, March 13th, 1998, October 13th, 2000 were all full moons. June 13th, 2003 and January 13th, 2006 were the days before a full moon, and June 13th, 2014 and January 13th, 2017 occur slightly after the full moon. Friday, September 13th, 2019 will be the next year to contain a full moon on a Friday the 13th.

Notable births and deaths on Friday the 13th

Name	Date	Note
Georges Simenon	February 13, 1903	Born
Margaret Thatcher	October 13, 1925	Born
Fidel Castro	August 13, 1926	Born
Arnold Schoenberg	July 13, 1951	Died
Steve Buscemi	December 13, 1957	Born
Julia Louis-Dreyfus	January 13, 1961	Born
Michelle Sara Cox	December 13, 1974	Born
Hubert Humphrey	January 13, 1978	Died
Mary-Kate and Ashley Olsen	June 13, 1986	Born
Ross Breeden	May 13, 1988	Born
Tupac Shakur	September 13, 1996	Died

External links

• Friday the 13th: Why is Friday the 13th considered an unlucky day? (Snopes.com)
• Paraskevidekatriaphobia (Fustar.org)
• Why Friday the 13th Is Unlucky (About.com)
• Friday the Thirteenth (Reb Chaim HaQoton)
• How Friday the 13th works (HowStuffWorks.com)
• National Geographic: Friday the 13th Phobia Rooted in Ancient History
• Friday the 13th and the Templars - About.com article
• Your Unlucky Day: The religious roots of triskaidekaphobia.
• Some don't count on Lucky 13 - Via Magazine.
• Paraskevidekatriaphobia - skepdic.com article on Friday the 13th
• http://www.infoplease.com/spot/friday13th.html
• A world of Luck: Friday the 13th - Snopes.com article