Thai lunar calendar

The Thai lunar calendar (Thai: ปฏิทินจันทรคติ Patitin Chantarakati) (literally, Against-the-Sun Moon-Ways) is Thailand's version of the lunisolar Buddhist calendar used in the southeast Asian countries of Cambodia, Laos and Burma. Based on the third-century Surya Siddhanta 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, Patitin Suriyakati (ปฏิทินสุริยคติ), Thailand's version of the Gregorian calendar, replaced the Patitin Chantarakati in AD 1888 / 2431 BE for legal and hence commercial purposes. Still, the four principal lunar phases determine Buddhist sabbaths (Uposatha), which are obligatory holy days for observant Buddhists. Especially significant ones are also feast days. Thai Chinese likewise observe their sabbaths and traditional Chinese holidays according to lunar phases. These move with respect to the solar calendar, so common Thai calendars incorporate Thai and Chinese calendar 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 animal for Chinese and Hora astrology (โหราศาสตร์ โหราสาต ho-ra-sat).


(For detailed discussion, see Lunar phase.)

Years nominally have twelve months and may have one of three lengths: 354, 355 or 384 days.

354-day normal-month year

354-day-long years have twelve normal months (See Months, below). A year of 354 days is a normal-month year (ปรกติมาสฅ (ปีปกกะติมาด Pee-pok-ga-ti-mat)).

355-day extra-day year

355-day-long years add an extra day to Month 7 (see below). A year having the extra day is an extra-day year (ปีอธิกวาร (ปีอะทิกะวาน Pee-a-ti-ga-wan)).

384-day extra-month year

384-day-long years add an extra month (อธิกมาส (อะทิกะมาด a-ti-ga-mat), which repeats 30-day-long Month 8 so that the count of months remains at 12. A year of 384 days having the extra month is an extra-month year (ปีอธิกมาส (ปีอะทิกะมาด Pee-a-ti-ga-mat).

New year

  • The Thai lunar calendar does not mark the beginning of a new year when it starts a new 1-to-12 count, most frequently in December (See Month 1, below).
  • The Thai solar calendar determines a person's legal age, and secular holidays, including the civil new year as well as the three days of the traditional Thai New Year's feast. Should holidays fall on a weekend, it also accommodates these as well as some of the Principal lunar festivals with a compensatory day off วันชดเชย.
  • Wan Khao Phansah วันเข้าพรรษา counts as a new year for monks; note that 2 August 2004 was the compensatory day off วันชดเชย for a Wan Khao Phansah that fell on a Sunday.
  • The Chinese calendar determines the day that a year assumes the name of the next animal in the twelve-year animal cycle.

Twelve-year animal cycle names

GregorianNew Year's DayThaiSign and name in English 1998January 28ปีขาล虎 Tiger 1999February 16ปีเถาะ兔 Rabbit 2000 February 5ปีมะโรง龍 Dragon (Big snake) 2001January 24ปีมะเส็ง蛇 Snake (Little snake) 2002 February 12ปีมะเมีย馬 Horse 2003 February 1ปีมะแม羊 Goat 2004January 22ปีวอก猴 Monkey 2005 February 9ปีระกา雞 Rooster 2006January 29ปีจอ狗 Dog 2007 February 18ปีกุน豬 Pig 2008 February 7ปีชวด 鼠 Rat 2009January 26ปีฉลู牛 Ox 2010 February 14ปีขาล虎 Tiger 2011 February 3ปีเถาะ兔 Rabbit


For more details on this topic, see month.
Note: this information applies only to the modern Thai lunar calendar, and is insufficient for deciphering lunar dates calculated in other modes.

Deuan (เดือน) means either month or lunation. Successive months (or lunations) number from 1 to 12. As in other Buddhist calendars, these have names that derive from Sanskrit, but which for the most part would be known only by Thai astrologers (Prasert Na Nagara 1998:524, cited in Diller).

Normal months

Two successive lunations take about 59 days. The Thai lunar calendar approximates this interval with normal-month (ปรกติมาสฅ ปกกะติมาด Pok-ga-ti-mat) pairs of 29 and 30 day months: 29 if an odd-numbered month (เดือนคี่ deuan kêe); 30 if an even-numbered month (เดือนคู่ deuan kôo). A 29-day lunation is called a hollow month (เดือนขาด deuan kàat); a 30-day lunation is called a full month (เดือนถ้วน deuan tûan). This is only marginally accurate, so at intervals either a normally hollow Month 7 takes an extra day, or an extra full Month 8 follows normal full Month 8. Note also that Months 1 and 2 are named in archaic alternate numbers, with the remainder being named in modern numbers.

Month 1 เดือน ๑

Deuan Aai (เดือนอ้าย) begins the cycle of counting the months anew, most frequently in December, but does not signify the beginning of a new year. Aai, an archaic word in Thai but not in other dialects, means first-born (or eldest). An odd-numbered hollow month (เดือนขาด deuan kàat), it is 29 days long.

Month 2 เดือน ๒

Deuan Yi (เดือนยี่) is from archaic ญี่ meaning 2. An even-numbered full month (เดือนคู่ deuan kôo), it is 30 days long.

Months 3–6 เดือน ๓ — ๖

Deuan 3–6 use the modern way to read numbers as do all remaining months. Months 3–6, as they alternate odd and even (เดือนคี่/คู่ deuan kêe/kôo) are alternately 29-day hollow months (เดือนขาด deuan kàat) or 30-day full months (เดือนถ้วน deuan tûan).

Month 7 เดือน ๗

Deuan 7, a hollow month, is normally 29 days long in years of 354 days, but adds an extra day (อธิกวาร (อะทิกะวาน A-ti-ga-wan)) when required for 355-day-long extra-day years (ปีอธิกวาร (ปีอะทิกะวาน Pee-a-ti-ga-wan).

Month 8 เดือน ๘

Deuan 8 is a 30-day full month (เดือนคู่ deuan kôo).

Month 8/8 เดือน ๘/๘

When an extra month (อธิกมาส (อะทิกะมาด a-ti-ga-mat)) is needed for a 384-day-long extra-month year (ปีอธิกมาส (ปีอะทิกะมาด Pee-a-ti-ga-mat)), Month 8 repeats as เดือน ๘/๘ Month 8/8, variously read as —
Deuan Bad dap Bad —Month 8 slash 8,
Deuan Bad Song Khang —Month 8 Side Two, or
Deuan Bad Song Hon —Month 8 Time Two in the Isan language.

Months 9–12 เดือน ๙ — ๑๒

Deuan 9–12 complete the lunar cycle.

Month divisions

Months divide into two periods designated by whether they are waxing or waning:Khang Kuen ข้างขึ้น : Waxing, the period from new moon to full moon, which is
15 days, always Khang Raem ข้างแรม : Waning, the period from full moon to new moon, which is
14 days in odd-numbered hollow months, except when Month 7 adds the extra day (อธิกวาร (อะทิกะวาน A-ti-ga-wan)); otherwise
15 days.

Note: when not compounded with other words or syllables: khang : ข้าง [at, on, or to the] sidekuen : ขึ้น to rise or mountraem : แรม to tire or retire.


A week is สัปดาห์ or สัปดาหะ, pronounced สับ-ดา sàb-da, สับ-ปะ-ดา sàb-phà-daa, or สับ-ดา-หะ sàb-da-hà. From a Sanskrit word for "seven", it is now defined by the On-line Royal Institute Dictionary (ORID) 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 wan prà to the next.


While solar-calendar weekdays have names, lunar-calendar days number sequentially from 1 to 14 or 15:Kuen 1 Kham Deuan 1 ขึ้น ๑ ค่ำ เดือน ๑ : Waxing 1 Evening [of] Month 1, on to Raem 15 Kham Deuan 12 แรม ๑๕ ค่ำ เดือน ๑๒ : Waning 15 Evening [of] Month 12.

Note: Kham ค่ำ Evening, nowadays is generally taken as 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. See Wan Wy Phra Chan, below.

Named lunar days

  • Wan Phra วันพระ Day(s) Holy [to Buddhists] ; also called
    • Wan Thamma Sawana วันธรรมสวนะ (วันทำมะสะวะนะ) religious holy day(s) ; Buddhist sabbath(s) ; regularly fall on:
      • Kuen 8 ขึ้น ๘ first-quarter moon
      • Kuen 15 ขึ้น ๑๕ full moon; also called
        • Wan Phen วันเพ็ญ day [of] full [moon].
          • Wan Duan 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; and
      • Raem 14 (15) แรม ๑๔ (๑๕) last day of the lunar month; also called
        • Wan Dab วันดับ day [moon is] quenched, [or goes] out.
  • Wan Wy Phra Chan วันไหว้พระจันทร์

Day [of] Respect [for] the Holy Moon
actual day the Harvest moon becomes full
Kuen 14 (15) Kham Deuan 11 ขึ้น ๑๔ (๑๕) ค่ำ เดือน ๑๐
Waxing 14(15) Evening, Month 11.

Holidays regulated by the moon

Buddhist Sabbaths, colloquial วันพระ Wan Phra, are the New, First-quarter, Full, and Third-quarter Moon-days. These are not normally days off วันยุด wan-yoot, except for butcher, barber and beautician shops that observe the Eight Precepts.

Annual holidays and seasonal festivals collectively are called วันนักขัตฤกษ์ วันนักขัดตะเริก Wan nak-khad-ta-roek.

Festivals or fairs are เทศกาล (เทสะกาน) thet-sa-garn; these may be further styled as ประเพณี pra-pen-nee traditional; and as พืธิ pit-ti, rite or ceremony. The table shows the principal ones governed by the moon in yellow.
Work holidays prescribed by the government as days off from work or school are วันยุดราชาการ Wan-yoot-ra-cha-gan; 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 วันชดเชย Wan chod-choey.

Work holidays and festivals regulated by the moon: x = waxing moon; n = waning
† 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 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.
Tai ไทย (ไท) [Archaic] free, frank; Thai race, language, alphabet ; citizen of Thailand.

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 (จันทะระคะติ) : 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 (ปะติทินจันทะระคะติ) : "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.]


  • Diller, Anthony; Preecha Juntanamalaga Thai Time. International Conference on Tai Languages and Cultures, Thammasat University. Australian National University. (1995). .
  • 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

See also

External links

Search another word or see thodon Dictionary | Thesaurus |Spanish
Copyright © 2015, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature

Mo. Day Event ไทย Comment
3† 1x Chinese New Year ตรุษจีน Most shops owned by Thai-Chinese close
3 15x Magha Puja วันมาฆะบูชา Makha Bucha
6 15x Vesak วิสาขะบูชา Visakha 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 Vegetarian Festival(เทศกาลกินเจ Thet-sa-gan Kin-je)
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 In Northern Thailand, this is Duean Yi and the Yee Peng Lantern Festival