Koh Samui Weather

Climate and Best Time to Visit Koh Samui

Gulf of Thailand Weather
Andaman Sea Weather

The weather in the Gulf of Thailand (east coast of Thailand. Koh Samui, Koh Phangan and Koh Tao) is quite different from the weather in the Andaman Sea (west coast of Thailand. Phuket, Krabi and Koh Lanta). There are different seasons depending on the region. Temperature ranges from 23°C to 32°C all year around in both Andaman Sea & Gulf of Thailand, but there are important differences in precipitation. Comparing the weather in Koh Samui with the weather in Phuket, average rainfall shows November is the rainiest month in Koh Samui. September in Phuket.

Check the graphs below comparing rainfall in different popular destinations in Thailand. The data is provided by the Thai Meteorological Department (2018).

Koh Samui Weather by Season​

Koh Samui is a tropical island with pleasant temperature all year around. Rain can be unpredictable and at times, torrential. There are 3 seasons in Koh Samui as in the rest of Thailand: Dry, Hot and Rainy, as well known as Cool, Hot and Wet.

Best Time to Visit Koh Samui

Ask yourself  what is more important to you between, heat, sunshine, rain, prices, holiday plan and how busy you prefer the island to be.

November is the wettest month of the year with rainfall most days. Some holiday makers, looking to relax enjoying activities like yoga retreats or SPA indulgences. Holiday makers chose to visit the island this month because is quieter and prices are lower. However, if you are coming from a country with cold or rainy conditions, looking for sun and water sports, probably is better to skip the rainy season and visit from January to September.

The best time to visit the island varies depending on your own preferences. If you are seeking for sunshine and a beach holiday aim for the hot and dry seasons. If you are into kite surfing, there are some spots with decent wind speed in Nathon, where you can surf during the quieter moths. If you prefer to enjoy a SPA retreat, any time is good. If you are tight on budget, perhaps the low season can be more appealing to your needs. Best thing about the island is you have so many options to chose from, regardless if you are looking for a beach day, adventure, water sports, visiting, eating or relaxing.

At anytime during the year, including the monsoon season, the average temperature ranges from 28°C to 30°C. At night it might be cooler if there is wind or little rain but the daytime temperature is mostly pleasant. The average Koh Samui weather is warm with tropical humidity. Sometimes rainy days are a blessing when is too hot!