Thailand Climate Patterns

Thailand is tropical and runs on three mainland seasons: cool from November to February, hot from March to May, and rainy from June to October.

"Cool" is relative — Bangkok still reaches the low thirties. The genuinely cool weather is in the northern hills, where December nights can approach freezing at altitude.

The rainy season is usually a heavy downpour in the late afternoon rather than continuous rain, and it does not make travel impractical on the mainland.

The coasts run different monsoons. The Andaman coast is wettest from May to October; the Gulf coast is wettest from October to December. This is the single most useful climate fact for planning a Thai beach holiday.

March and April bring severe agricultural burning haze to the north, with air quality in Chiang Mai regularly among the worst in the world during those weeks.