Home › Weather › Koh Samui Weather By Month
Live forecasts update automatically; written guidance last reviewed 23 June 2026 by the Australia Voice Weather Desk. Data from the Bureau of Meteorology (BOM) and other national met services via Open-Meteo.
Live data from Open-Meteo · updates automatically ·
Koh Samui’s tropical climate brings warm weather year-round, with a distinct wet season from October to December. The live forecast above shows current conditions at Koh Samui Airport, which reflects island-wide patterns. For most visitors, the driest and sunniest months are January through April.
What is the weather like each month on Koh Samui?
Koh Samui has three main seasons: hot-dry (January–April), hot-wet (May–September), and monsoon (October–December). Temperatures stay between 26°C and 33°C across the year. The southwest monsoon from May to September brings regular but short afternoon showers. The northeast monsoon from October to December delivers heavier rain, especially in November.
For dry, sunny days, travel between January and April. Koh Samui weather in February and March offers the lowest humidity and calm seas. If you prefer fewer crowds and don’t mind some rain, Koh Samui weather September and Koh Samui weather November still have plenty of warm hours between showers. Koh Samui weather December is the wettest month, often with prolonged downpours.
How reliable is a 30-day forecast for Koh Samui?
A koh samui weather forecast 30 days gives a general seasonal trend, not precise daily predictions. Tropical weather can shift quickly, especially during monsoon transitions. For trip planning, use the koh samui weather by month rain averages above, then check the live forecast above a few days before departure.
What is the best month to visit Koh Samui for sun?
February and March are the best months for sun. They have the lowest rainfall, low humidity, and clear skies. Temperatures sit around 30–32°C, ideal for beach and outdoor activities.
Does it rain every day in Koh Samui during November?
Yes, rain is frequent in November, often as heavy afternoon or evening storms. Many days still have sunny mornings. Expect around 20–22 rainy days in the month, with short bursts rather than all-day drizzle.
Is Koh Samui rainy in March?
March is one of the driest months on Koh Samui, with only about 50mm of rain. You’ll see mostly sunny days and low humidity, making it a popular time for travel. Temperatures are warm but not extreme.
For more Australian weather information, visit our Australia weather hub or check the Sydney Weather page. For tropical cyclone updates, see our Severe Weather Warning page.