Worst time to visit Koh Samui
Some months in Koh Samui are clearly tougher for travel — extreme heat, cold, drenching rain, or peak storm season. Here's what to skip.
Months to avoid
| Month | Why |
|---|---|
| January | extremely wet (24 rain days) |
| February | very wet (17 rain days) |
| March | very wet (17 rain days) |
| April | very hot (31°C / 87°F)extremely wet (23 rain days) |
| May | very hot (31°C / 87°F)extremely wet (29 rain days) |
| June | very hot (30°C / 86°F)extremely wet (27 rain days) |
| July | extremely wet (28 rain days) |
| August | extremely wet (28 rain days) |
| September | extremely wet (29 rain days) |
| October | extremely wet (31 rain days) |
| November | extremely wet (29 rain days) |
| December | extremely wet (24 rain days) |
What to expect in the worst months
April. Highs in the 31°C range are tolerable in the shade but draining if you're walking all day. 23 rain days out of 30 means roughly 77% of days see measurable rainfall — plan flexible indoor backups for every outdoor day.
May. Highs in the 31°C range are tolerable in the shade but draining if you're walking all day. 29 rain days out of 31 means roughly 94% of days see measurable rainfall — plan flexible indoor backups for every outdoor day.
June. Highs in the 30°C range are tolerable in the shade but draining if you're walking all day. 27 rain days out of 30 means roughly 90% of days see measurable rainfall — plan flexible indoor backups for every outdoor day.
Better times to go
No month in Koh Samui hits the typical 18–28 °C / low-rain comfort zone — every season has trade-offs. Choose what you can tolerate: heat, cold, rain, or storm risk.
Better in the same region in April
If you're set on Asia in April, these cities have more comfortable conditions in the same window:
If you still have to go — what to bring
- Heat: UPF-rated long-sleeve sun shirt, refillable insulated bottle, electrolyte tablets, lightweight wide-brim hat. Plan indoor activities for 11 a.m.–4 p.m.
- Wet: Real rain shell (not a "water-resistant" jacket), packable umbrella, dry-bag for electronics, quick-dry layers. Pre-book indoor museums and food halls.
Related Koh Samui guides
The positive counterpart: which months are great and why.