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Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the Metro Report weather desk. Data from national met services via Open-Meteo.
Live data from Open-Meteo · updates automatically ·
What is the typical weather pattern on Koh Samui?
Koh Samui weather is defined by two main seasons: a dry season from December to February and a wetter period from October to November, with a secondary rainy peak in May. Daytime highs hover around 30–33°C throughout the year, and sea temperatures stay above 27°C, making swimming possible any month. January and February offer the most reliable sunshine, while the southwest monsoon (May–August) brings occasional showers but still plenty of warm, humid days.
When is the best time to visit Koh Samui?
For the lowest rainfall and clearest skies, plan your trip between December and February. This period coincides with the island’s peak tourist season, so expect higher prices. March and April are also good, with less rain but increasing heat. If you’re looking at koh samui weather by month, October and November are the wettest, often with prolonged downpours. For those checking koh samui weather 14 days or koh samui weather 15 days ahead, the live forecast above gives a reliable short-term outlook, while koh samui weather forecast 30 days can indicate broader trends but is less precise.
Is Koh Samui rainy in November?
Yes, November is one of the wettest months on Koh Samui, with heavy, often prolonged rainfall and occasional storms. However, temperatures remain warm (around 30°C), and there are still sunny intervals between showers. Many visitors find it acceptable if they want lower prices and fewer crowds.
What is Koh Samui weather like in January?
January is part of the high season, offering some of the best weather: low rainfall, plenty of sunshine, and daytime highs around 30°C. Sea conditions are calm, and humidity is lower than in the wet season. It’s ideal for beach holidays and outdoor activities.
Can I get a 14-day forecast for Koh Samui?
The live forecast above provides a detailed 14-day outlook for Koh Samui Airport. While longer-range forecasts (30 days) give general trends, a 14-day forecast is more reliable for planning daily activities and checking for any approaching weather systems.
For the latest conditions across the UK, visit our UK weather hub or check the 10 Day Weather Forecast UK.