Average monthly water temperature in Koh Samui, Thailand
On this page you find the mean water temperature over the year in Koh Samui (Surat Thani Province), Thailand. Discover the unique water temperature patterns, from its warmest to its coolest months.
Koh Samui offers consistently warm water temperatures year-round. The warmest month, April, averages 30°C (86°F).
Even in the coolest water temperature month, January, the average temperature is 27°C (81°F). These conditions are perfect for water activities and relaxation throughout the year.
Koh Samui Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Koh Samui - and find the best time to visit.
Koh Samui 3-Day Forecast
Temperature Rainfall Sunshine Humidity Water Temp
See the full Koh Samui climate overview or explore weather in Thailand.
Popular this month
Where to go in July - average daytime high across popular destinations.
Bangkok
34°C (93°F) Chiang Mai33°C (91°F) Jomtien Beach
32°C (90°F) Hua Hin32°C (90°F) Koh Samui30°C (86°F) Ko Lanta30°C (86°F) Ao Nang Beach30°C (86°F) Patong Beach30°C (86°F) 
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