Month guide · Koh Samui · Thailand
Koh Samui in September
What September is really like in Koh Samui: weather, crowds, prices, events and what to pack.
Updated By the AMZBooking editorial team
Photo: Gunther Dihlmann, CC BY-SA 3.0
Quick answer
September is a good-value shoulder-season month. Expect average highs of 32°C (90°F), lows of 24°C (75°F), about 14 rainy days and roughly 12.2 hours of daylight. Showers increase and visitor numbers fall; still plenty of sunshine between storms.
Key facts
- Average high / low
- 32°C (90°F) / 24°C (75°F)
- Rainy days
- About 14
- Daylight
- About 12.2 hours
- Sea temperature
- 29°C (84°F)
- Crowds
- Quiet
- Hotel prices
- Low
Weather in September
September is the 6th-warmest month in Koh Samui: days average 32°C (90°F) against a yearly average high of 31°C (88°F), and nights fall to about 24°C (75°F). Rain falls on roughly 14 of its 30 days. Compared with August (32°C (90°F)), September is about as warm; by October highs stay near 31°C (88°F).
- Sunrise (15 September)
- About 06:10
- Sunset (15 September)
- About 18:20
- Daylight
- About 12.2 hours
- Sea
- 29°C (84°F)
Transition (September). More frequent showers and fewer visitors; a quiet month with lower rates.
Crowds and prices
On a 1–5 scale, September rates 2 for crowds (the peak is February at 5) and 2 for hotel prices (highest in February). That makes September one of the better-value months to book.
Events in September
September has no major recurring festival in Koh Samui, which usually means easier bookings.
What to do in September
With frequent rain, plan around indoor sights and keep outdoor time flexible.
Beach · Lamai
Silver Beach (Crystal Bay)
Arrive before 10am to get a spot; it gets crowded later.
- Time needed
- 2–3 hours
- Cost
- Free
- Free
- Outdoors
- Couples
- Photo spot
Viewpoint · Chaweng
Lad Koh Viewpoint
A roadside viewpoint on the coast road south of Chaweng, looking north along Chaweng Noi and over granite boulders to the sea.
- Time needed
- 20 minutes
- Cost
- Free
- Free
- Views
- Photo spot
Beach · Chaweng
Coral Cove
Bring your own snorkel and wear reef shoes; avoid standing on coral.
- Time needed
- 2 hours
- Cost
- Free
- Free
- Outdoors
- Nature
- Off the beaten path
Religious site · South coast
Laem Sor Pagoda
On the quiet south coast, this chedi covered in yellow tiles stands right at the water's edge, with views of offshore islands.
- Time needed
- 30 minutes
- Cost
- Free
- Free
- Photo spot
- Off the beaten path
- Views
The sea averages 29°C (84°F) — warm enough to swim. Best beaches near Koh Samui.
What to pack
For highs near 32°C, lows near 24°C and 14 wet days: light, breathable clothes, a sun hat and high-factor sunscreen; a compact umbrella and waterproof shoes — rain is frequent; comfortable walking shoes.
Is September a good time to visit Koh Samui?
A good-value shoulder-season month. If your dates are flexible, February–April and June–August are better overall. Compare every month.
Koh Samui in other months
Questions travellers ask
+Is September a good time to visit Koh Samui?
It is a good-value shoulder-season month. Showers increase and visitor numbers fall; still plenty of sunshine between storms.
+How warm is Koh Samui in September?
Average highs are around 32°C (90°F) and lows around 24°C (75°F).
+Does it rain a lot in Koh Samui in September?
Expect rain on about 14 days of the month, so pack for wet weather.