The rainy season does not mean rain for your entire trip, but timing and amounts vary from day to day. Add meals and indoor breaks between outdoor visits, and read wind and wave conditions as well as rain for a sea trip. Even within Thailand, Phuket and Koh Samui have different wetter periods.
Most of Thailand broadly follows a rainy season from mid-May to mid-October, a winter season from mid-October to mid-February, a summer season from mid-February to mid-May. The actual starting dates vary each year. Bangkok remains hot during winter days, while Chiang Mai has cooler mornings and nights, so pack for each destination separately.
Phuket and Krabi on the Andaman coast receive more rain during the southwest monsoon. Koh Samui on the southern east coast is affected by the northeast monsoon, with more rainfall toward the end of the year. Choosing a different coast can change the weather conditions even in the same month.
Climate normals give Phuket 350.4 mm of rain in September and Koh Samui 444.6 mm in November. Compare each region’s 12-month table, then read the actual forecast and boat operating advice for your dates.
No. Northern and central Thailand, the Andaman coast and the southern east coast have different wetter periods. If choosing between Phuket or Krabi and Koh Samui, compare which coast gets less rain in your travel month.
You do not have to avoid it. Eat or rest indoors during heavy rain, then explore nearby places as it eases. Keep outdoor sightseeing times flexible. Swimming, boats and island tours may need cancellation or changes according to the day’s weather and local instructions, so read cancellation and change terms when booking.
No. The figures average weather observed from 1991–2020. They help compare travel months but do not predict your actual day. Before departure, read the Thai Meteorological Department’s forecast for your dates.
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