Best time to visit
Thailand in August
Chiang Mai's wettest month of the year, at 276mm, which surprises people who think of the north as the dry part of Thailand. Koh Samui is unchanged at 90mm and is again the answer.
Measured, not repeated
Where it rains in August, and how much
Driest first. Koh Samui takes 90mm this month and Chiang Mai takes 276mm, which is 3 times as much. The strip on the right is that place's whole year, with August outlined, so you can see whether this is a good month for it or merely a bad one everywhere.
- Koh Samui 90mm 18 rain days
- Bangkok 157mm 24 rain days
- Thailand's islands 245mm 23 rain days
- Phuket 248mm 23 rain days
- Krabi 263mm 26 rain days
- Chiang Mai 276mm 26 rain days its wettest month
ERA5 reanalysis, 1995 to 2024, averaged per calendar month at each place's own coordinates. A rain day is a day with a millimetre or more.
August is the northern peak: 276mm and twenty-six rain days in Chiang Mai, more than Phuket's 248 and more than the islands' 245. The idea that the south is the wet part of the country and the north is the dry part is true for six months of the year and exactly wrong for this one.
The Gulf has not moved. Koh Samui has recorded 85, 90 and 90mm in June, July and August, three of the steadiest months on this site, while everywhere else has been between 150 and 280.
Bangkok at 157mm and twenty-four rain days is not a washout, but it is a month of afternoon storms rather than of rain all day, which is a distinction the millimetre figure hides and the rain-day figure only half reveals.
Where to go in August
The three driest places on this site this month, in order.
What is on in August
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Queen Sirikit's birthday and Mother's Day
12 August
A public holiday.