Ko Samui
September
Weather in Ko Samui for September 2025
Your guide to Ko Samui weather in September - trends and predictions
In general, the average temperature in Ko Samui at the beginning of September is 28.6 °C. As the month progressed, temperatures tended to slightly decrease, reaching an average of 28.4 °C by the end of September.
Ko Samui experiences an exceptionally high level of rainfall in September, with more than 20 rainy days on average.
Is September a good time to visit Ko Samui? check out the best time to travel to Ko Samui page.
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6
Dry days
24
Rainy days
0
Snow days
28°/27°
Temperatures
27 km/h
Avg max wind
75 %
Avg humidity
Ko Samui in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  29° | 2 28° | 3  28° | 4 28° | 5 29° | 6 29° | 7  29° |
| 8  29° | 9 29° | 10 29° | 11 29° | 12 29° | 13  29° | 14 28° |
| 15 28° | 16 28° | 17 28° | 18 29° | 19  28° | 20 29° | 21 30° |
| 22 29° | 23 29° | 24 28° | 25 28° | 26 28° | 27 28° | 28 29° |
| 29 29° | 30 29° |
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Temperatures trend during September in Ko Samui
See the weather trend as well as the moving average line
September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. | Moderate or heavy rain shower | 29° /27° | 10.2 mm | 6 | |
| 2 Sept. | Moderate or heavy rain shower | 28° /27° | 6.5 mm | 6 | |
| 3 Sept. | Light rain shower | 28° /26° | 5 mm | 6 | |
| 4 Sept. | Light rain shower | 28° /27° | 6.6 mm | 6 | |
| 5 Sept. | Moderate or heavy rain shower | 29° /26° | 24.6 mm | 7 | |
| 6 Sept. | Light rain shower | 29° /27° | 7.4 mm | 6 | |
| 7 Sept. | Cloudy | 29° /27° | 2 mm | 6 | |
| 8 Sept. | Overcast | 29° /28° | 0.9 mm | 6 | |
| 9 Sept. | Patchy rain possible | 29° /28° | 1 mm | 7 | |
| 10 Sept. | Light rain shower | 29° /27° | 6 mm | 6 | |
| 11 Sept. | Patchy rain possible | 29° /27° | 0.6 mm | 7 | |
| 12 Sept. | Cloudy | 29° /27° | 0.3 mm | 6 | |
| 13 Sept. | Partly cloudy | 29° /27° | 3.6 mm | 7 | |
| 14 Sept. | Moderate or heavy rain shower | 28° /26° | 6.4 mm | 6 | |
| 15 Sept. | Overcast | 28° /26° | 1.6 mm | 6 | |
| 16 Sept. | Light rain shower | 28° /26° | 5 mm | 6 | |
| 17 Sept. | Light rain shower | 28° /27° | 3.2 mm | 6 | |
| 18 Sept. | Patchy rain possible | 29° /27° | 5.7 mm | 6 | |
| 19 Sept. | Patchy light drizzle | 28° /27° | 6.5 mm | 6 | |
| 20 Sept. | Patchy rain possible | 29° /27° | 1.2 mm | 6 | |
| 21 Sept. | Light rain shower | 30° /27° | 8.2 mm | 6 | |
| 22 Sept. | Light rain shower | 29° /27° | 5.2 mm | 6 | |
| 23 Sept. | Light rain shower | 29° /27° | 7.2 mm | 6 | |
| 24 Sept. | Light rain shower | 28° /27° | 9.9 mm | 6 | |
| 25 Sept. | Patchy rain possible | 28° /26° | 4.7 mm | 6 | |
| 26 Sept. | Light rain shower | 28° /26° | 9.8 mm | 7 | |
| 27 Sept. | Light rain shower | 28° /26° | 5.7 mm | 6 | |
| 28 Sept. | Light rain shower | 29° /26° | 4.8 mm | 6 | |
| 29 Sept. | Patchy rain possible | 29° /27° | 7.1 mm | 7 | |
| 30 Sept. | Cloudy | 29° /27° | 0.9 mm | 7 | |
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Important Notice
Our weather forecast for Ko Samui in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Ko Samui forecast closer to your planned date for the most up-to-date weather information.
Ko Samui in September - FAQ
What are the expected maximum and minimum temperatures in Ko Samui during September?
During September, expect a variety of temperatures with highs around 28° and lows near 27°, suitable for diverse activities and preferences.
How much rainfall should be expected in Ko Samui during September?
Significant rainfall exceeding 258.1 mm is expected in Ko Samui during September, occurring over more than 24 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Ko Samui during September?
The average wind speed in Ko Samui during September is 27 km/h, suggesting breezy to windy conditions, depending on your activities.
What to pack to Ko Samui in September?
As you prepare for your trip to Ko Samui in September, it's important to consider the typical weather patterns for the time of year. Below is a carefully tailored packing list to ensure that your time in Ko Samui, during September, is comfortable and enjoyable, regardless of the weather conditions.
- Clothing
- Lightweight Clothing: T-shirts, blouses, shorts, skirts
- Rain Gear: Lightweight, waterproof clothing
- Footwear
- Waterproof Shoes
- Accessories
- Sunglasses: For sun protection
- Sun Hats: Wide-brimmed hats for sun protection in warm weather
- Umbrellas/Raincoats: For rainy days
- Personal Items
- Sunscreen: High SPF for sunny destinations
- Lip Balm with SPF: To protect against chapped lips
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Where is Ko Samui?Get accurate weather forecasts for Ko Samui, located at latitude 9.536 and longitude 99.936. Stay updated with localized weather information tailored for Ko Samui.
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