Very hot in Aug
37°C average high
avg high · 21° at night
25°C+ on almost every day · often 35°C+
Thailand
Koh Samui weather in August
Is it warm? Yes. August in Koh Samui is hot: afternoons average 33°C and nights 25°C. Most days (80%) peak between 32°C and 34°C.
Hot · average high
33°C
25°C or more on almost every day.
- Average low25°overnight
- Sea30°average, 2022–2025
- Rainy days9104 mm in the month
- SkyMostly cloudy87% cloud · 1% clear days
How warm it really gets
Every August afternoon from 2011–2025: 465 days. Most (80%) peaked between 32° and 34°.
August, year by year
The average August high in each year. The warmest, 2023, averaged 33°C; the coolest, 2011, 32°C.
Compared with home
Average August highs. Expect rain on about 9 days (104 mm in a typical month).
- Koh Samui33°
- London24°
- Manchester20°
- Dublin20°
- Cork20°
- Glasgow19°
- Belfast19°
Warmer in August, not much further
Flying times are estimates from Dublin; Koh Samui is about 13h.
Very hot in Aug
39°C average high
avg high · 22° at night
25°C+ on almost every day · often 35°C+
Very hot in Aug
36°C average high
avg high · 23° at night
25°C+ on almost every day · often 35°C+
Air: Copernicus ERA5-Land, 2011–2025, matched to the official averages for Koh Samui. Sea: Copernicus ERA5, 2022–2025. Rainy days = days with 1 mm of rain or more, as weather stations count them. Clear day = average cloud cover of 30% or less. These are averages of past weather, not a forecast. Methodology