Thai solar calendar

The Thai solar calendar, Suriyakati (: สุริยคติ), has been the official and prevalent in  since it was adopted by King  in, although the Western calendar year is sometimes used in business, and quite often in banking.

Thai calendars show both the Buddhist Era (BE, พุทธศักราช Phuttasakarat), abbreviated Pho So (พ.ศ.); and the (คริสต์ศักราช, kritsakarat), abbreviated Kho So (ค.ศ.). They also show Chinese numerals for the Common Era and. As lunar dates determine s (วันพระ Wan Phra), as well as many, both and  dates are shown.
 * Wan Pra are marked with a Buddha image, and Chinese holidays with red s.
 * Scrawled blue figures (in this example 078 on the 15th and, above left, 538 on the 19th and 2576 on the 31st) mark dates national lottery numbers were drawn.
 * Lunar dates and the year's are recorded on Thai birth certificates after the official date. The Thai reckon their ages by the Twelve-Animal sequence, though the official calendar determines age at law; as, for instance, the  Birthday, August 12, a public holiday also celebrated as Thai Mothers' Day.

The months and days of the week are the same as those used in the western. Names of the months derive from of the signs of the zodiac. are named after the Sun and Moon, and translations of the names of the five classical planets. The year is counted from the, which is 543 years earlier than the Christian Era. For example, A.D. is equivalent to 2550 B.E. The era is based on the passing away (Parinibbana) of, which is dated to  by the Thai (although some sources state that Buddha died in ). It is important to remember that only from, onwards does this 543 addition/subtraction rule work perfectly — see below.

The calendar,decreed by King (Rama V), was called Ratana Kosindra Sok (รัตนโกสินทรศก), and was nearly identical with the western. Year counting, however, was in reference of the date of the founding of (Ratana Kosindra),   (the first day of Year 1 Ratana Kosindra Era (รัตนโกสินทร์ศักราช), abbr. (ร.ศ.) ro so). King (Rama VI) changed the year counting to Buddhist Era in  and fixed the start of a year to April 1.

In (2484 B.E.) as  loomed on the horizon, Prime Minister  per decree made January 1 the official start of a new year (so year 2483 B.E. had only nine months). When converting a date prior to that year, check whether it falls between January 1 and March 31: if so the number to add or subtract is 542, not 543.



Today, both the Common-Era New Year's Day (January 1) and the traditional (สงกรานต์) celebrations (April 13-15) are public holidays on the official calendar. Public holidays on the official calendar for Buddhist and Chinese are still calculated according to the lunar calendar, so their dates change with respect to the solar calendar every year.

Thirty-day-month names end with -ยน -yon, which is from the Sanskrit root -ayana, meaning the arrival of; 31-day-month names with -คม -khom, which is from Sanskrit -agama which also means the arrival of. February's name ends with -พันธ์, fettered or bound. The day added to February in a solar leap year is named Athikasuratin อธิกสุรทิน; respelled to aid pronunciation อะทิกะสุระทิน.

Note: The colours are the traditional Thai birthday colours associated with the :, , , , , and.

External link

 * Thai Time by Anthony Diller