Thai Standard Time

     The local standard time for each country dates back to the 19th century; to eliminate the confusion of solar time, which varied in every city from east to west, local standard time was increasingly necessary when trains began operating in 1843. The first standard time was used in England, with the whole country using Standard Time based in Greenwich. Later, Sir Sanford Framing, a Canadian railway planner and engineer, initiated the idea of using standard time worldwide.

     In the International Prime Meridian Conference, Washington, D.C., in November 1884, the standard time of each country was compared to the Universal Time Coordinated (UTC), in which 25 countries agreed to divide the world along the longitude into 24 equal zones. Each zone is 15 degrees west and east and equal to 1 hour away from the adjacent zone, and it was agreed that the 0-degree line would pass through Greenwich, England. The International Date Line is at 180 degrees, down the middle of the Pacific Ocean.

     Countries have embraced this concept by using longitudinal lines that divide the world into two parts, the east and west hemispheres. It determines whether the local standard time is earlier or later than the global standard time in Greenwich. But local time is set and changed according to the conditions of different countries. Each country still has the right to set the local standard time.

     In Thailand, the Hydrographic Department regulates Thailand's standard time. It corrects changes in time, and each year it coordinates with the International Bureau of Weights and Measurement (BIPM) in Paris, France.

     By promulgating the standard time of Thailand, King Rama VI issued the standard time ordinance for Thailand, enacting a Royal Decree to use the rate time announced in the Government Gazette, Volume 36, on 21 March 1919 and effective from 1 April 1920 (New Year's Day at that time), stating "The rate time for Siam throughout the Kingdom is 7 hours before Greenwich time in England."

     Thailand has set the country's standard time to UTC+7 hours (7 hours ahead of the global standard time).

Source: Thai Meteorological Department, 4353 Sukhumvit Road, Bangna, Bangna, Bangkok 
Tel. +66 2399 4012

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