Home › Weather › Koh Samui Weather
Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the NewsPrism weather desk. Data from national met services via Open-Meteo.
Live data from Open-Meteo · updates automatically ·
Koh Samui weather is typically warm year-round, with a tropical monsoon climate that brings distinct wet and dry seasons; the live forecast above shows current conditions at the island’s airport.
What is the best time to visit Koh Samui?
The driest and most popular months are December to February, offering lower humidity and plenty of sunshine. March to August brings hotter, often humid weather, while the monsoon season from October to early December sees the highest rainfall, particularly in November.
How does the weather vary by month?
Temperatures remain fairly constant, averaging 27–30°C throughout the year, but rainfall patterns shift significantly. For Koh Samui weather by month, the southwest monsoon (May–October) brings frequent showers, while the northeast monsoon (October–December) can cause heavier, prolonged rain—especially in November. For Koh Samui weather in December and January, expect drier conditions and cooler evenings. If you’re checking Koh Samui weather in October or November, be prepared for tropical downpours and possible rough seas.
Does Koh Samui have a monsoon season?
Yes, it experiences two monsoons. The southwest monsoon (May–October) brings scattered showers, while the northeast monsoon (October–December) delivers heavier, more persistent rain, especially in November.
What is the sea temperature around Koh Samui?
Sea temperatures range from 27°C in January to 30°C in May, making swimming and snorkelling comfortable year-round, though visibility can drop during the rainy months.
Can I get a reliable 14-day forecast for Koh Samui?
Long-range forecasts for Koh Samui weather 14 days ahead have lower accuracy due to tropical variability. For planning, check the live forecast above and use the 7–10 day outlook as a general guide.