Samui island has mainly 3 seasons throughout the year, the dry season(December until February), the hot season (March until August) and the rainy season (September until November). There’s no such thing as winter in Koh Samui but you will find the sea breeze here is refreshing even in the hot summer.
Dry Season (December until February
The dry season is the perfect weather. making it a generally safe time to visit and be assured of hot and sunny days while you can enjoy the activity outside with windy condition. It does not rain a lot, which means that waters quite calm, but it some occasional heavy rains for an hour or two might occur.
Generally, it occurs some refreshing wind or breeze and you should enjoy a lot of sunshine at this time of the year.
Hot Season (March until August)
Hot season in Samui can be super hot at noon but the sun will slightly fade down after 4 pm. The best time to get under the sun and enjoy water activity is in the morning -11 am. and 3 pm. onward to avoid sunburnt.
With quite dry, sunny and hot weather the months between March and August are called the hot season. March and April are in experience the hottest and driest months and in May it might start to rain more often. These showers are mostly not lasting very long but can be heavy falls or thundershowers.
Hot Season the best season to visit Koh Samui, Koh Phangan, Koh Tao, and the National Marine Park, if you are able to take the heat and stand temperatures between 28℃ – 40℃ during the day.
Rainy Season (September until November)
From September the temperatures are still hot and usually many sunny days through the month. October and November are the months with the rainiest days and with the biggest volume of rainfall around the year.
Rainy Season or monsoon season does not mean it will be raining at all times, but rainfalls and thundershowers are very common and there might be times with non-stop rain for 5-6 days. Nevertheless, this season is highly appreciated after a long period with hot and dry weather, you might even find yourself in a refreshing monsoon shower for a moment.
Most of the rain showers are short (rain showers in October and November might be lasting longer) and due to the finite water supplies of Koh Samui those rain showers are needed and important for Koh Samui’s flora and fauna. As the Angthong Marine Park is closed each year between November and mid-December, Bluestars does not operate during November and mid-December.