Koh Samui · Month comparison
September vs April
April ranks #1 overall vs September at #9. Songkran brings Thai New Year festivities — warm, slightly wetter, but culturally unmissable.
September
#9 of 12 months
Worth considering
Shoulder low season: heavy rain returns and the crowds evaporate — beach time is a lottery.
- ↑Prices drop sharply from August peak: genuinely excellent value at resort-quality properties
- ↑Island almost entirely to yourself — a radically different, more local experience
April
#1 of 12 months
Best match
Songkran brings Thai New Year festivities — warm, slightly wetter, but culturally unmissable.
- ↑Songkran water festival (13–15 April) transforms Na Thon and Chaweng into celebrations of Thai New Year
- ↑Good value accommodation: 30–35% below peak-season rates with weather still mostly excellent
| Factor | September | April |
|---|---|---|
| Weather score | 3 | 7 |
| Value score | 8 | 6 |
| Crowd score | 8 | 6 |
| Events score | 3 | 7 |
| Atmosphere | 5 | 8 |
| Avg high temp | 30.8°C | 32.8°C |
| Monthly rain | 185mm | 83mm |
| Daily sunshine | 5.5hrs | 7.5hrs |
September trade-offs
- ↓185mm of rain — heavy and sustained, not just afternoon showers; full days can be lost
- ↓Sea getting choppy: some beach swimming unpleasant on rougher days
- ↓Some operators reduce tour schedules and watersports become unreliable
April trade-offs
- ↓Songkran week: hotel prices spike temporarily and transport books up fast
- ↓83mm of rain is manageable but occasional heavy afternoon showers begin appearing
- ↓Peak heat of 32.8°C: demanding for any strenuous outdoor activity between 11am and 3pm
Scores compare months within Koh Samui. Climate data: Open Meteo ERA5 30-year normals (1991–2020). Methodology →