You should advoid rainy season which you will see the red flag show that you cannot swim. The rainy season in Koh Samui typically occurs from October to December, with the heaviest rainfall usually in November. This period is characterized by frequent and sometimes heavy showers, although it can still have sunny days in between.

I think February March, or September and October.

Hello! The best month to visit Koh Samui would be either January or February. During these months, the weather is typically sunny and dry, making it ideal for beach activities and outdoor exploration. November can still be quite rainy as it’s the tail end of the monsoon season. So, for the best experience, January and February are your best bets. Enjoy your trip!