Average Temperature in Koh Samui by Month

Koh Samui has a tropical monsoon climate, classified as Am in the Köppen system. The warmest month is April with an average high of 27°C, while the coldest month is January with lows dropping to 23°C. The annual temperature range of 4°C indicates a relatively stable climate year-round.

The driest month is February with only 6 rain days and 36mm of precipitation. For travellers, February through to the following month typically offers the best balance of warm temperatures and dry conditions. Average humidity ranges from 82% to 82% throughout the year.