Koh Samui Weather and Climate
Travel and Local Information Guide
Koh Samui has a tropical monsoon climate. Humidity is high and temperatures average around 28 degrees Celsius. The weather is generally good year round, and the one thing you will rarely feel is cold.
Located on the Gulf of Thailand, Koh Samui offers world-class diving sites with optimum conditions between March and August (the worst September to November).
There are three seasons…
The Dry Season
The Dry Season here runs roughly from December to February. With slightly cooler temperatures, little rain, calm seas, and light winds many consider this the best time to come. For hotels this is peak season.
The Hot Season
The hottest time of year is between March and April; a great time to visit if you can stand 30 degree plus temperatures. Around late April/early May there is normally a sudden – and, for the locals at least, welcome – increase in precipitation. From May until September the weather typically sees strong daytime sunshine, until late afternoon thunderstorms roll in – a kind of mini-monsoon season.
The Rainy Season
September through to November sees the heaviest rainfall, although even now it doesn’t fall everyday and often only in short bursts. The weather can be unpredictable, with slightly rougher sees and winds. Although still great for the beach holiday (less people, lower hotel rates), this is not the best time to come for diving, as visibility is reduced by around 30%.