Thai lunar calendar
The Thai lunar calendar (Thai: ปฏิทินจันทรคติ, RTGS: patithin chanthrakhati, pronounced [pà.tì.tʰīn tɕān.tʰrá.kʰā.tìʔ], literally, Against-the-Sun Moon-Ways), Dai calendar (傣历), or Tai calendar, is Thailand's version of the lunisolar Buddhist calendar. It is used in the southeast Asian countries of Cambodia, Laos and Burma for calculating lunar-regulated holy days. Based on the third-century Surya Siddhanta (a Hindu calendar), these combine lunar and solar calendars for a nominal year of 12 months. An extra day or an extra 30-day month is intercalated at regular intervals; Thai, Lao, and Cambodian versions do not add an extra day to years with an extra month.
Legal v. religious calendar 
The Thai solar calendar (Thai: ปฏิทินสุริยคติ, RTGS: patithin suriyakhati, [pà.tì.tʰin sù.rī.já.kʰā.tìʔ]), Thailand's version of the Gregorian calendar, replaced the patithin chanthrakhati in AD 1888 / 2431 BE for legal and commercial purposes. In both calendars, the four principal lunar phases determine Buddhist Sabbaths (Uposatha), obligatory holy days for observant Buddhists. Significant days also include feast days. Thai Chinese likewise observe their Sabbaths and traditional Chinese holidays according to solar terms, two of which correspond to one lunar phase. These move with respect to the solar calendar, so common Thai calendars incorporate both Thai and Chinese lunar dates for religious purposes.
Mundane astrology also figures prominently in Thai culture, so modern Thai birth certificates include lunar calendar dates and the appropriate Chinese calendar zodiacal animal year-name for both Thai Hora (Thai: โหราศาสตร์, RTGS: horasat) and Chinese astrology.
To keep the years in sync with the seasons, Thai lunar years may add a day to the 7th month or repeat the 8th month. Therefore, years may have one of three lengths – 354, 355 or 384 days – yet retain a nominal length of twelve months.
- 354 day-long years consist of 12 "normal months", and such a year is called a "normal-month year" (Thai: (ปี) ปกติมาส, RTGS: (pi) pakatimat, [(pī) pà.kà.ti.mâːt]).
- 355 day-long years add an extra day to the normally 29-day-long 7th month; such a year is called an "extra-day year" (Thai: (ปี) อธิกวาร, RTGS: (pi) athikawan, Thai pronunciation: [(pīː) ʔà.tʰí.kà.waːn]).
- 384 day-long years repeat the 30-day-long 8th month, thus keeping the month count at 12. Nevertheless, a year of 384 days is called an "extra-month year" (Thai: (ปี) อธิกมาส, RTGS: (pi) athikamat, [(pīː) ʔà.tʰí.kà.mâːt]).
New year 
The Thai lunar calendar does not mark the beginning of a new year when it starts a new 1-to-12 count, which occurs most frequently in December.
The Thai solar calendar determines a person's legal age and the dates of secular holidays, including the civil new year and the three days of the traditional Thai New Year. Should the holidays fall on a weekend, it also accommodates these as well as some of the principal lunar festivals with a compensatory day off (Thai: วันชดเชย, RTGS: wan chotchoei).
Twelve-year animal cycle 
13 April of the solar calendar occasions the beginning of the traditional Thai New Year (Songkran) and is the day that a year assumes the name of the next animal in the twelve-year animal cycle; Thai Chinese communities may observed the name-change earlier in accordance with the Chinese New Year.
|Gregorian year||Chinese New Year's Day||Thai beginning 13 April||Animal|
|1998||January 28||Pi Khan ... ปีขาล||虎 Tiger|
|1999||February 16||Pi Tho..... ปีเถาะ||兔 Rabbit|
|2000||February 5||Pi Marong ปีมะโรง||龍 Dragon (Big snake)|
|2001||January 24||Pi Maseng ปีมะเส็ง||蛇 Snake (Little snake)|
|2002||February 12||Pi Mamia ปีมะเมีย||馬 Horse|
|2003||February 1||Pi Mamae ปีมะแม||羊 Goat|
|2004||January 22||Pi Wok..... ปีวอก||猴 Monkey|
|2005||February 9||Pi Raka..... ปีระกา||雞 Rooster|
|2006||January 29||Pi Cho..... ปีจอ||狗 Dog|
|2007||February 18||Pi Kun..... ปีกุน||豬
|2008||February 7||Pi Chuat.. ปีชวด||鼠 Rat|
|2009||January 26||Pi Chalu..... ปีฉลู||牛 Ox|
|2010||February 14||Pi Khan..... ปีขาล||虎 Tiger|
|2011||February 3||Pi Tho ปีเถาะ||兔 Rabbit|
|2012||January 23||Pi Marong ปีมะโรง||龍 Dragon (Big snake)|
|2013||February 10||Pi Maseng ปีมะเส็ง||蛇 Snake (Little snake)|
|2014||January 31||Pi Mamia ปีมะเมีย||馬 Horse|
|2015||February 19||Pi Mamae ปีมะแม||羊 Goat|
In the modern Thai calendar, months (Thai: เดือน, RTGS: duean, [dɯ̄an], meaning "month" or "Lunation") are defined by lunar cycles. Successive months (or lunations) are numbered from 1 to 12 within the Thai year. As in other Buddhist calendars, these months have names that derive from Sanskrit, but for the most part are only known by Thai astrologers.
Two successive lunations take slightly more than 59 days. The Thai lunar calendar approximates this interval with "normal-month" pairs (ปกติมาส, RTGS: pakatimat) that are alternately 29 and 30 days long. 29-day "hollow months" (เดือนขาด, RTGS: duean khat, [dɯ̄an kʰàːt]) are odd-numbered (เดือนคี่, RTGS: duean khi, [dɯːan.kʰî]); 30-day "full months" (เดือนถ้วน, RTGS: duean thuan, [dɯ̄an tʰûan]) are even-numbered (เดือนคู่, RTGS: duean khu, [dɯ̄an kʰûː]).
To keep the beginning of the month in sync with the new moon, from time to time either the normally "hollow" Month 7 takes an extra day, or an extra "full" Month 8 follows a normal "full" Month 8.
Months 1 – 6 
Month 1, "duean ai" (เดือนอ้าย, [dɯ̄an ʔâːj]), begins the cycle of counting the months anew, most frequently in December, but does not signify the beginning of a new year. ai, an archaic word in Thai but not in other dialects, means first-born (or eldest). An odd-numbered hollow month, it is 29 days long.
Months 3–6, "duean 3–6", use the modern reading of Thai numerals, as do all remaining months. Months 3–6, alternate between 29-day hollow months and 30-day full months.
Month 7 and athikawan 
Month 8 
The eighth month, "duean 8", is a 30-day full month.
Month 8/8 "athikamat" 
Athikamat (อธิกมาส, Thai pronunciation: [à.tʰí.kà.mâːt])) is the extra month needed for a 384-day-long pi athikamat (extra-month year; ปีอธิกมาส, Thai pronunciation: [pī.à.tʰí.kà.mâːt]). Month 8 repeats as เดือน ๘/๘ or Month 8/8, variously read as "duean paet thab paet" (เดือนแปดทับแปด) — "Month 8 slash 8", "duean paet song khang" (เดือนแปดสองข้าง) — "Month 8 Side Two", or "duean paet song hon" (เดือนแปดสองหน) — "Month 8 Two Times".
Months 9 – 12 
Months 9–12, "duean 9–12", complete the lunar cycle.
Month divisions 
Months divide into two periods designated by whether they are waxing or waning:
- Waxing : khang khuen (ข้างขึ้น), the period from new moon to full moon, is always 15 days long.
- Waning : khang raem (ข้างแรม), the period from full moon to new moon, which is 14 days long in hollow months, except when Month 7 adds an extra day, and 15 days long in full months.
A week is called Sapda/Sappada (Thai: สัปดาห์, [sàp.dāː, sàp.pà.dāː]). From a Sanskrit word for "seven", it is now defined by the Royal Institute Dictionary (RID) as a 7 day period beginning on Sunday and ending Saturday. When referring to lunations, however, it is the 7-, 8- or (rarely) 9-day interval between quartile lunar phases; that is, from one วันพระ to the next.
While solar-calendar weekdays have names, lunar-calendar days number sequentially from 1 to 14 or 15 in two segments depending on whether the moon is waxing or waning. For example, "raem 15 kham duean 12 แรม ๑๕ ค่ำ เดือน ๑๒" means "Waning 15 Evening [of] Month 12".
Kham ค่ำ , evening, is considered to be the evening of the common day that begins and ends at midnight, rather than of a day that begins and ends at dusk. Past practice may have been different.
Named lunar days 
- Wan Phra วันพระ, Buddhist holy days
- Wan Thamma Sawana วันธรรมสวนะ (วันทำมะสะวะนะ) Buddhist Sabbath regularly fall on:
- Khuen 8 ขึ้น ๘ first-quarter moon
- Khuen 15 ขึ้น ๑๕ full moon; also called wan phen วันเพ็ญ day [of] full [moon]. However, Wan Deuan Phen วันเดือนเพ็ญ, the actual day of the full moon and khuen 15 kham do not always fall on the same day.
- Raem 8 แรม ๘ third-quarter moon
- Raem 14 (15) แรม ๑๔ (๑๕) the last day of the lunar month; also called wan dap วันดับ day [moon is] quenched, [or goes] out.
- Wan Thamma Sawana วันธรรมสวนะ (วันทำมะสะวะนะ) Buddhist Sabbath regularly fall on:
- Wan wai phra chan วันไหว้พระจันทร์, called "Day [of] Respect [for] the Holy Moon", is the actual day the Harvest moon becomes full. It occurs on khuen 14 (15) kham duean 10 ขึ้น ๑๔ (๑๕) ค่ำ เดือน ๑๐ (Waxing 14 (15) Evening, Month 10.)
Holidays regulated by the moon 
Buddhist Sabbaths, colloquially called วันพระ, are the New, First-quarter, Full, and Third-quarter Moon-days. These are not normally days off (วันหยุด), except for butcher, barber, and beautician shops that observe the Eight Precepts. Annual holidays and seasonal festivals collectively are called วันนักขัตฤกษ์.
Work holidays prescribed by the government are called Thai: วันหยุดราชการ; those regulated by the moon are red.
Weekends are normally days off; if a holiday normally observed by a day off falls on a weekend, the following Monday is a compensatory day off Thai: วันชดเชย.
|Work holidays||and||festivals||regulated by the moon: x = waxing moon; n = waning|
|3†||1x||Chinese New Year||ตรุษจีน||Most shops owned by Chinese-Thai close|
|3||15x||Magha Puja||วันมาฆบูชา||Makha Bucha|
|8‡||15x||Asalha Puja||อาสาฬหบูชา||Asarnha Bucha|
|8‡||1n||Wan Kao Pansa||วันเข้าพรรษา||Begin Rains Retreat, or "Buddhist Lent"|
|10||15n||Thetsagarn Sart||เทศกาลสารท||The Vegetarian Festival (เทศกาลวันสารท) now appears on calendars as thetsakan kin che 9 wan (เทศกาลกินเจ ๙ วัน), (begin) Nine-day Vegetarian Festival. Kin Jae  means (to vow) in the manner of Vietnamese or Chinese Buddhists to eat a strict vegetarian diet. (เทศกาลกินเจ)|
|11||15x||Wan Awk Pansa||วันออกพรรษา||End Rains Retreat, or "Buddhist Lent"|
|11||1n||Thod Kathin||ทอดกฐิน||Presentation of Monk's Robes after Rains Retreat|
|12||15x||Loy Krathong||ลอยกระทง||Note that Loy Krathong dates are based on the Lanna (Northern Thailand) Lunar Calendar which is two months later than the Thai Lunar Calendar. Loy Krathong is actually on the second month of the Lanna calendar which is the 12th month of the central Thai calendar.|
- † The Chinese New Year uses different methods of determining intercalary months, so this festival sometimes occurs a month earlier or later.
- ‡ Month 8/8 in years with the extra month.
Thai year vocabulary 
Thai orthography spells most native words phonetically, though there is no definitive system for transcription into Roman letters. Here, native Thai words are immediately followed by a vocabulary entry in this pattern:
- Phonetic Thai (Thai phonetic respelling, if different) [Comment] definition; variant definitions.
Sanskrit loan words follow different rules [the way English grammatical rules vary for words of Greek and Latin origin ('ph-' in 'phonetic' being pronounced /f/, for example.)] Entered below in order of first appearance, these vocabulary entries are in this pattern:
- Sanskrit สันสกฤต (สันสะกริด /san-sa-krit/)
Literally means "self-made" or "self-done", or "cultured" in a modern usage (which implies the language of cultured persons); Sanskrit alphabet, language, writing; [presumed] compound of
- san สัน (-/son/) derived from the word, "saṃ" meaning "self, together, with"
- skrit สกฤต (สะกริต /sa-krit/) derived from the word "(s)kar" meaning "do or make".
- Chantarakati จันทรคติ (จันทระคะติ)
- Lunar Calendar; compound of
- Chantara- จันทร- (จันทะระ /chontara/) : Chon จันทร์ (จัน) moon, lunar +
- Kati คติ (คะติ) : ways, principles; moral [of a tale].
- Patitin ปฏิทิน (ปะติทิน)
- Calendar; compound of
- Pati- ปฏิ- (ปะติ-) : anti-, re- +
- -tin (-ทิน) : [from tinnagorn ทินกร (ทินะกอน) - poetical for] the sun, Sol
- [possibly in the sense of 'tint' + - gorn -กร – -er, -or: paint-er].
- Patitin Chantarakati ปฏิทินจันทรคติ (ปะติทินจันทระคะติ)
- "Resolarized Moon-Ways", Lunisolar Calendar
- Suriyakati สุริยคติ (สุริยะคะติ)
- Solar Ways, Solar Calendar; compound of
- Suriya สุริย or สุริยะ : Athit อาทิตย์, the sun, Sol +
- Kati คติ (คะติ) : ways, principles; moral [of a tale].
- Prokatimas ปรกติมาส (ปฺรกกะติมาด /pro-ko-ti-maht/)
- normal month; compound of
- Prokati ปรกติ (ปฺรกกะติ) : pokiti ปกติ (ปะกะติ) ordinary, usual, normal +
- Mas มาส (มาด /maht/) : du-an (เดือน) month.
- Athikamas อธิกมาส (อะทิกะมาด /a-ti-ka-maht/)
- month added in leap-month lunar years
- Athikawara อธิกวาร (อะทิกะวาน /a-ti-ka-wahn/)
- day added in leap-day lunar years; compound of
- Athika (Sanskrit: adhika) : additional +
- -wara วาร (วาน /wahn/) : wan วัน day.
- Athikasuratin อธิกสุรทิน (อะทิกะสุระทิน)
- day added to February in a solar leap year.
See also 
|Wikisource has original text related to this article:|
- Public holidays in Thailand
- The Royal Institute of Thailand
- Thai solar calendar
- Thai 6-hour clock
- Time in Thailand
- Traditional Burmese calendar
- J.C. Eade. The calendrical systems of mainland southeast asia. E.J. Brill, Leiden. p. 22. ISBN 90-04-10437-2. According to some scholars including George Coedes, the change originally occurred at the beginning of the 5th lunar month, a few days before Songkhran.
- Diller, Anthony; Preecha Juntanamalaga (2000). "Thai Time". Faculty of Asian Studies Australian National University. p. 25. Archived from the original on 2002-01-10. Retrieved 2008-05-08. "(5.1) ...names would be known only by Thai astrologers (Prasert Na Nagara 1998:524)."
- On-line Royal Institute Dictionary (ORID - 1999).
- RID on-line
- สารท ๑
Further reading 
- Diller, Anthony; Preecha Juntanamalaga (December 1995). "Thai Time". International Conference on Tai Languages and Cultures, Thammasat University. Australian National University. Archived from the original on 2002-12-10. Retrieved 22 June 2008.
- Eade, J.C. The calendrical systems of mainland south-east Asia. ISBN 90-04-10437-2 (Cited by Diller & Preecha)
- Sethaputra, So. New Model English - Thai Dictionary, ISBN 974-08-3253-9
- Thai Time by Anthony Diller – last changed 10 January 2002.
- How Chula Sakarat Dates Work in Thailand: article for stamp collectors recovered 20 December 2007.
- Thai Lunar Calendar (BE.2300-2584) (Thai Language)