Koh Samui in September
Quiet month
By Daan · Last reviewed October 2026
The short answer
September is a reasonable month in Koh Samui — with trade-offs.
September is quiet and cheaper, with more frequent showers.
September in detail
What September actually feels like
- Weather
- 25–32°C
- Hot, around 32°C, with showers.
- Crowds
- Moderate
- Quiet.
- Prices
- $$$
- Low rates.
+Low prices.
–More showers.
My tip for September
Look for good hotel deals.
- Spas
- Quiet beaches
How September compares
Against the other eleven months
9th of 12 overall in Koh Samui, 9th for weather, 3rd for space, 3rd for value. The emptiest month is November; the best value is November.
See all twelve months for Koh SamuiNot set on September?
Even stronger months in Koh Samui
Also good in September
Weather
Weather in Koh Samui in September
In September Koh Samui averages a high of 32°C (90°F) and a low of 25°C (77°F), with about 118 mm of rain or snow over 11 wet days. The warmest month is May (around 33°C) and the coolest is January (around 29°C); the wettest month is November.
- Average high
- 32°C
- 90°F
- Average low
- 25°C
- 77°F
- Precipitation
- 118 mm
- Wet days
- 11
Climate data: World Meteorological Organization (Ko Samui, 1991–2020). Temperatures are averages of daily highs and lows.
Quick answers
Koh Samui in September: the questions people ask
- Is September a good time to visit Koh Samui?
- September is a reasonable month in Koh Samui — with trade-offs. It ranks 9 of 12 months in Koh Samui overall (9 for weather, 3 for space, 3 for value). The main upside: Low prices. The main downside: More showers.
- What is the weather like in Koh Samui in September?
- Average highs are around 32°C and lows around 25°C. Expect about 118 mm of rain or snow over roughly 11 wet days. Hot, around 32°C, with showers. For comparison, the warmest month is May (around 33°C) and the coolest is January (around 29°C).
- Is Koh Samui crowded in September?
- Crowds are moderate. Quiet. The quietest month is November.
- How expensive is Koh Samui in September?
- Prices are at level 3 of 5 ($$$). Low rates. The best-value month is November.
- When is the best time to visit Koh Samui?
- In the CrowdFreeViews month scores, February is the best month overall (September ranks 9 of 12). The quietest month is November and the best value is November.