Koh Samui Weather and Climate
Travel and Local Information Guide
Koh Samui has a tropical climate with three distinct seasons: dry, hot and rainy. Thailand is situated between the Tropic of Cancer and the Equator (slightly closer to the latter), a geographical position making its climate warm and humid all year round. The humidity level is generally between 70 and 85 per cent, and the temperatures average around 28°C.
Located in the Gulf of Thailand, Koh Samui offers all that vacationers from northern countries could dream of regarding weather conditions. They are generally good year round, and the one thing you will rarely feel is cold. The optimum weather conditions can be enjoyed between December and August.
The Dry Season
The Dry Season in Samui runs roughly from December to February. With warm yet bearable temperatures, little rain, calm seas, and light winds. Many consider this the best time to come. For hotels and every tourist-related businesses, 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°C+ temperatures. Around late April/early May, there is normally a sudden – and, for the locals at least, welcome – increase in precipitation. Paradoxically, from June to August is also considered a mini-high season in Samui. The weather usually follows a pattern: strong daytime sunshine followed by late afternoon thunderstorms. It is indeed very agreeable.
The Rainy Season
September through to November sees the arrival of the monsoon and, therefore, the heaviest rainfall. Even at this time, it doesn’t fall every day and often only in short bursts. The weather can be unpredictable, with slightly rougher seas and winds. Although still great for a beach holiday (less people, lower hotel rates), this is not the best time to come for diving and snorkelling, as visibility is reduced by around 30 per cent.