Koh Samui experiences two distinct seasons. February to late June is the peak travel season when the atmosphere remains hot and dry. While strong winds occur during October and January, July to October witness intermittent showers with some amount of rain during November as well.
Koh Samui unlike other places in Thailand has a distinctly different climatic condition. This is due to its east facing position and location on the Gulf Coast that makes it prone to the Northeast monsoon.
The following paragraph provides brief information regarding the temperature and atmospheric condition during the various months of the year: January – February: Samui Island has a cool season. Average temperature is around 26°Cl.
March – May: Koh Samui experiences a hot season with temperatures reaching up to 40°C. There is less rain.
June – September: Days are sun filled except for the occasional downpours, which usually doesn't last long.
October – December: Frequent showers occur that last until sometime around mid December, giving way to extended periods of dry and often sunny weather. The sea becomes rough and visibility may be affected.
The ideal time to visit Koh Samui is from February until the end of June.