Koh Samui in September: weather, sea & travel advice
Koh Samui in September is especially suited to beach holidays, family holidays and city breaks. Days are around 29 °C (warm), and the sea is about 29 °C. With about 11 rainy days it is wet.
Koh Samui · SeptemberPhoto: Sonia Selivonchik · CC BY-SA 4.0Climate facts
- Day
- 29 °C
- Night
- 27 °C
- Sea
- 29 °C
- Rainy days
- 11 rainy days
- Sun
- 6 h/day
- Humidity
- 81 %
Suitability by travel type
BeachGood78/100
City breakGood72/100
ActiveLimited53/100
FamilyGood73/100
In favour
- Pleasant daytime temperatures around 29 °C
- Warm, swimmable sea (29 °C)
To consider
- Higher chance of rain (about 11 rainy days)
- High humidity (81 %)
All months at a glance
27J
28F
29M
30A
30M
30J
29J
29A
29S
28O
28N
28D
6J
4F
6M
8A
10M
8J
8J
9A
11S
16O
19N
13D
Similar destinations in September
Frequently asked questions
How warm is Koh Samui in September?
Daytime highs average around 29 °C, with nights around 27 °C.
Can you swim in Koh Samui in September?
The sea is about 29 °C (very warm).
Does it rain a lot in Koh Samui in September?
On the long-term average, expect about 11 rainy days.
When is the best time to visit Koh Samui?
The most favourable months are usually the ones highlighted on the overview page. Values are historical averages, not a forecast.