Ko Samui in September
6.1out of 10
Possible, with caveats
Warm and comfortable: highs around 28°C. Very wet: about 23 rainy days.
28°CAvg high
26°CAvg low
23Rainy days (141 mm)
12:03 hDaylight
06:13Sunrise · 18:16 Sunset
Why this score
- Warm and comfortable: highs around 28°C
- Very wet: about 23 rainy days
What to wear and pack
- T-shirts and light layers
- Shorts or a light skirt
- Rain jacket or compact umbrella
- Sunscreen, sunglasses and a hat
How reliable is the forecast?
Rain in September varies a lot between years (±3.2 rainy days), so check the forecast closer to your trip. Averages cover 30 years (1991–2020). Individual days can differ a lot.
Year at a glance
Weather by month
| Month | Avg high | Avg low | Rainfall | Rainy days | Humidity | Sunshine | Score |
|---|---|---|---|---|---|---|---|
| January | 27°C | 26°C | 73 mm | 10 | – | – | 7.8 |
| February | 27°C | 26°C | 36 mm | 5 | – | – | 8.4 |
| March | 28°C | 27°C | 89 mm | 9 | – | – | 7.9 |
| April | 29°C | 27°C | 96 mm | 12 | – | – | 7.4 |
| May | 29°C | 27°C | 115 mm | 21 | – | – | 6.0 |
| June | 29°C | 27°C | 89 mm | 19 | – | – | 6.4 |
| July | 29°C | 27°C | 84 mm | 19 | – | – | 6.6 |
| August | 29°C | 27°C | 92 mm | 18 | – | – | 6.6 |
| September | 28°C | 26°C | 141 mm | 23 | – | – | 6.1 |
| October | 28°C | 26°C | 288 mm | 26 | – | – | 6.1 |
| November | 28°C | 26°C | 288 mm | 21 | – | – | 6.1 |
| December | 27°C | 26°C | 144 mm | 13 | – | – | 7.0 |
Frequently asked questions
How hot is Ko Samui in September?
Daytime highs average 28°C and nights about 26°C.
When is the best time to visit Ko Samui?
The best months are February, March.