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 season
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%.
