Weather in Koh Samui in September

Average daily temperatures

Days are usually hot with balmy evenings, so visitors should pack light and cool clothing. The average daily maximum is 33 C and the average daily minimum is 25 C.

Sunshine and rainfall

There is a 21% chance of a perfect sunny day and a 79% chance of seeing some clouds, with on average 47mm of rainfall this month.

Best time to be on the beach

It’s a great time of year to swim in the sea, with the water at an average temperature of 29 C.