A rainy-season holiday does not mean rain throughout your stay, but its timing and amount vary daily. Fit meals and indoor rests between outdoor visits, and check wind and waves as well as rain for sea trips. Phuket and Koh Samui have different wet periods despite both being in Thailand.
Most of Thailand broadly has 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. Actual seasonal start dates vary each year. Bangkok can be hot by day even in winter, while Chiang Mai’s mornings and nights are cooler, so do not plan the same clothing for both.
Rain increases on the Andaman coast around Phuket and Krabi during the south-west monsoon. Koh Samui on the southern east coast is affected by the north-east monsoon and has higher rainfall towards the end of the year. Changing your coastal destination can change the conditions even within the same month.
Climate normals give Phuket 350.4mm of rain in September and Koh Samui 444.6mm in November. Compare each region’s 12-month table, then look at the forecast for your actual travel dates and boat operations.
No. Northern and central Thailand, the Andaman coast and the southern east coast have different wet periods. If choosing between Phuket or Krabi and Koh Samui, compare which has less rain in your travel month.
Not necessarily. Eat or rest indoors during heavy rain and explore nearby when it eases. Keep outdoor sightseeing times flexible. Swimming, boat trips and island tours may need to be changed or cancelled according to weather and local instructions, so read cancellation and amendment terms when booking.
No. These figures average observations from 1991–2020. They help compare travel months but do not tell you the weather on your travel day. Before departure, check the Thai Meteorological Department’s forecast for your actual dates.
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