Weather locations in Thailand

Thailand lies wholly within the tropics and has a tropical monsoon climate: high temperatures throughout the year, a clear dry season and a marked rainy season, split into three seasons by the south-westerly and north-easterly monsoons.

Three seasons

The cool season, from November to February, is driven by the north-easterly monsoon bringing dry air down from China; nights cool sharply, especially in the north. The hot season, from March to mid-May, is the driest and hottest, with daytime highs often above 35 °C in the Central Plains, and is the time of Forum-style thunderstorms in April. The rainy season, from May to October, is driven by the south-western monsoon arriving from the Andaman Sea and the Bay of Bengal.

Regional differences

The Central Plains are hot and humid, with rain concentrated in the rainy season. The northern highlands are noticeably cooler in the cool season and take most of their rain from the south-western monsoon and local convection. On the southern peninsula the two coasts have opposite wet seasons: the east coast, including Songkhla, is wettest from May to December, while the west coast, including Phuket and Krabi, is wettest from October to January.

Temperatures

Bangkok averages about 26 °C to 27 °C all year, with January lows near 20 °C and April highs near 35 °C. Chiang Mai averages roughly 18 °C in December and 28 °C in May.

Rainfall

Annual totals range from about 1,200 mm in the Central Plains and north-east to 2,000 mm or more on the peninsula's windward slopes and mountain areas. Rain usually arrives as short, heavy afternoon downpours rather than steady all-day drizzle.

When to go

Early December to early February is generally the driest and most comfortable time for most of the country. The Andaman coast is best from November to April, while the Gulf coast is best from January to September.