Best time to visit
Thailand in September
The worst month in the country by the numbers. Bangkok records its own wettest month, the Andaman is near its peak, and even Koh Samui has begun to climb. If the dates are fixed and the destination is not, the Gulf is still the least bad.
Measured, not repeated
Where it rains in September, and how much
Driest first. Koh Samui takes 139mm this month and Krabi takes 296mm, which is 2 times as much. The strip on the right is that place's whole year, with September outlined, so you can see whether this is a good month for it or merely a bad one everywhere.
- Koh Samui 139mm 22 rain days
- Bangkok 263mm 26 rain days its wettest month
- Chiang Mai 269mm 24 rain days
- Thailand's islands 276mm 24 rain days
- Phuket 293mm 25 rain days
- Krabi 296mm 26 rain days
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.
Bangkok 263mm, its annual maximum. Krabi 296mm, Phuket 293mm, the islands 276mm, Chiang Mai 269mm. Five of the six places on this site are above 260mm in the same month, which happens in no other month of the year.
Koh Samui at 139mm is the exception and the last of its dry run. September is the ninth and final month of the Gulf's dry season, and the figure has already doubled from August. In October it triples again.
September is the cheapest month to be in Thailand and it is priced that way for a reason. It suits a city trip, a food trip or a temple trip better than a beach one.
Where to go in September
The three driest places on this site this month, in order.
What is on in September
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Phuket Vegetarian Festival
Late September or October, over nine days · Phuket Town date moves each year
Set by the Chinese lunar calendar. Processions, street food and body-piercing rituals at the Chinese shrines.