Thailand is lucky enough to have 18 or 20 day public holidays throughout the year celebrating Buddhist religious events, monarchy events as well as Songkran (Thai New Year). Some of the dates are fixed but many of the Buddhist holidays are related to the lunar month and subsequently the date changes annually. Many of the national holidays are 'dry days', in particular, religious holidays, where alcohol is not allowed to be served or sold as a mark of respect.
Bangkok also seems to have its fair share of government elections and these could be for the General Election, a Bangkok Governor or perhaps small local district elections. The polls are open on Sundays but the bars and clubs are not allowed to sell alcoholic drinks from 6pm on the Saturday until the polls close later on Sunday afternoon or evening. This ban on alcohol extends to foreign visitors as well as Thai nationals.
January: 1st/2nd – New Years (fixed)
February: Makha Bucha Day (Buddhist Holiday) and Full Moon 3rd month (depends on Thai lunar calendar)
April: 6th – Chakri Day (fixed), 13th/14th/15th – Song Kran Holiday (Thai New Year, fixed)
May: 1st – National Labour Day (fixed), 5th Coronation Day (fixed), Makha Bucha Day (Buddhist Holiday) and Full Moon 6th month (depends on Thai lunar calendar)
July: Makha Bucha Day (Buddhist Holiday) and Full Moon 8th month (depends on Thai lunar calendar)
August: 12th HM the Queen's birthday (fixed)
October: 23rd – Chulalongkorn Day (fixed)
November: Loy Krathong Festival and Full Moon 12th month –(depends on Thai lunar calendar)
December: 5th – HM the King's birthday (fixed), 10th - Constitution Day (fixed), 31st (New Years Eve -fixed)