Koh Samui Weather in August
Thinking of visiting Koh Samui in August? Expect very high temperatures reaching 30°C (86°F) during the day, dropping to 27°C (81°F) at night, and note that quite a bit of rainfall is likely.
Rainfall in Koh Samui in August
The climate data from previous years indicates about 17 days of rain, averaging 103 mm (4.1 in) for the month. This is a wet month with frequent and often heavy showers. Both the number of rain days and the total rainfall are high.
Temperature in Koh Samui in August
If you're visiting Koh Samui in August, expect highs of 30°C (86°F) and overnight lows around 27°C (81°F). It's usually most comfortable outside during the morning and later in the day. With overnight lows of 27°C (81°F), nights stay very warm. Air conditioning makes a real difference if you're sensitive to heat. A cold shower before bed can also help you get to sleep more comfortably.
Sunshine in Koh Samui in August
The month experiences a moderate amount of sunlight, with 152 hours of sunshine. This provides a nice balance between sunshine and clouds.
Average water temperature in August
At 29°C (84°F), the water is very warm — more like a heated pool than the sea. Great for those who like warm water, though some may find it less refreshing on a hot day.If your ideal day consists of dry skies and pleasant temperatures, January and February typically offer the best circumstances for Koh Samui.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Thailand, check out our Koh Samui's climate page.
Koh Samui Temperature in August
Min Temperature
27°C (81°F)
Max Temperature
30°C (86°F)
Water Temperature
29°C (84°F)
Chance of Rain
56%
Precipitation
103 mm (4.1 in)
Rainy days
17 days
Humidity
78%
Sunshine
152 hours
Percentage Sunshine
Daily Historical Temperatures
49-year average (1976-2025)
Based on our historical records, temperatures in Koh Samui typically stay consistent throughout August, with daily highs averaging around 30°C (86°F). Nights are warm, with lows around 26°C (79°F).
Average temperatures in August
Daily Historical Precipitation
49-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in August
Historical weather for Koh Samui in August
Browse day-by-day weather records for Koh Samui spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Koh Samui historical weather extremes in August
Our historical data for Koh Samui spans 1982 to 2025, revealing these weather extremes.
- On August 4, 1990, temperatures climbed to 40°C (104°F), marking the warmest August day on record.
- The coldest August day was on August 24, 1997, with a maximum of 25°C (77°F).
- Nighttime temperatures dropped to 23°C (73°F) on August 4, 1994, marking the coldest August night on record.
Best Places in Thailand in August
Find out more about the weather in Thailand and which places have the best travel conditions in this month. See all of Thailand in August →
perfect weather
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What to Wear in Koh Samui in August
Warm but pleasant conditions in Koh Samui in August. Focus on lightweight, maybe with natural fabrics, cotton blend shirts, comfortable shorts, and breathable footwear. A light cover-up for sun protection is smart too. Expect heavy rainfall, so bring good rain protection and waterproof bags. With water temperatures around 29°C (84°F), swimming conditions are excellent. Pack your swimsuit, goggles, and maybe some water shoes. Bring sunglasses since you'll have some sunny periods throughout the monthWhat To Do in Koh Samui in August
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Thailand, check out our Koh Samui's climate page.
Temperature Rainfall Sunshine Humidity Water Temp
See the full Koh Samui climate overview or explore weather in Thailand.
