Year-round weather and climate in Ko Samui, Thailand
Average temperatures in Ko Samui run from an average low of 25°C77°F in January up to an average high of 33°C91°F in April. April is the driest month at 6 rainy days; October the wettest at 29. Here is the annual climate data, so you know what you are packing for.
Good to know
- Population
- 50K
- Currency
- THB
- Language
- Thai
- Time zone
- Bangkok
Best time to visit
To avoid the most intense heat, the best time to visit is during the milder season around February, March, and April.
Rain character
Tropical Downpours: Expect intense bursts of rain during wetter months. Pack quick-drying footwear and a compact umbrella.
Day-to-night swing
Thermal Flatline: Day-to-night temperatures barely budge. Evenings are just as warm as the afternoon, meaning you can confidently leave the evening jacket in your hotel.
Seasonality Profile
Tropical Monsoon: Consistent heat year-round. Defined entirely by its dramatic shift between extreme dry and torrential wet seasons.
Evening vibe
Cozy Indoor Culture: Evenings are generally crisp, damp, or sweltering. Nightlife centers around indoor venues.
Sightseeing stamina
Summer Heat Fatigue: Midday heat in March, April, May, and June is intense. Pack high-SPF sunscreen and a wide-brimmed hat.
Average temperatures, sunshine, and rainfall
Average monthly weather in Ko Samui, based on recent historical data. Essential insights on temperature swings, expected rainfall, and daily sunshine.
Bars span the average daily low to high. Apr is typically driest at 6 days (23mm); Oct the wettest at 29 days (235mm).
| Month | Average high | Average low | Sunshine hours | Rainy days | Total rainfall |
|---|---|---|---|---|---|
| Jan | 29°C / 84°F | 25°C / 76°F | 10h | 15 | 56mm |
| Feb | 30°C / 86°F | 25°C / 77°F | 11h | 13 | 44mm |
| Mar | 31°C / 88°F | 26°C / 79°F | 11h | 9 | 24mm |
| Apr | 33°C / 92°F | 27°C / 81°F | 12h | 6 | 23mm |
| May | 32°C / 90°F | 27°C / 81°F | 11h | 22 | 110mm |
| Jun | 31°C / 88°F | 27°C / 80°F | 9h | 18 | 113mm |
| Jul | 30°C / 86°F | 26°C / 79°F | 8h | 23 | 188mm |
| Aug | 30°C / 87°F | 26°C / 78°F | 10h | 23 | 170mm |
| Sep | 29°C / 85°F | 26°C / 78°F | 9h | 25 | 211mm |
| Oct | 29°C / 85°F | 25°C / 77°F | 10h | 29 | 235mm |
| Nov | 29°C / 84°F | 25°C / 76°F | 8h | 26 | 279mm |
| Dec | 28°C / 83°F | 25°C / 77°F | 9h | 25 | 187mm |
Weather data by Open-Meteo.com (opens in a new tab)
Frequently Asked Questions
When is the sunniest time of year to visit Ko Samui?
The most sunshine in Ko Samui comes around April, averaging 12 hours a month. If you're heading there then, pack your sunglasses and sunscreen.
What clothes should I pack for Ko Samui?
Your packing list depends entirely on when you travel. Temperatures in Ko Samui swing from an average low of 25°C77°F in January up to 33°C91°F in April. The Packola app builds a tailored packing list for you based on the live weather forecast for your exact travel dates.
Do I need to pack an umbrella for Ko Samui?
Ko Samui gets rain on about 234 days out of the year. The wettest month is October. If you're traveling during the rainy season, you'll definitely want to pack an umbrella and a light rain jacket.
Pack smarter.
Averages get you close, but the week you travel is what matters. Get the live forecast, a smart packing list, and discover the best local spots and activities in Ko Samui with Packola.
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