Climate and seasons (affects travel times and sea crossings)
Reviewed by the Samui Local Hub team ·
Main page on this topic: Weather by month
Fact
Koh Samui has a tropical monsoon climate. Unlike Phuket and the Andaman coast (wet May-October), Samui's heaviest rain falls roughly from mid-October to early December, with November the wettest month. The driest, most reliable beach months are about February to April. Average daily temperatures are about 28 C year round. Rough monsoon seas in November-December can delay or cancel ferries and close Ang Thong Marine Park for several weeks.
Value
Wettest ~Oct-Dec (peak Nov); driest ~Feb-Apr; mean ~28 C
Notes
Annual rainfall ~1,960-1,990 mm (WMO 1991-2020 normals as cited by Wikipedia).
Sources
Plus local research.
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Free trip plannerMore guides: Geography & distances
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- Distance to the mainland (Donsak)
- Island size: 228.7 km2 vs 247 km2 (source discrepancy)
- Location: Gulf of Thailand, Surat Thani Province