Koh Tao weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Good
Best time to visit: December – April
What is the weather like in Koh Tao in September?
In September, Koh Tao is hot: daytime highs average 28 °C, and even at night it stays warm at around 26 °C. The sea averages 29.1 °C – almost as warm as a bath. Expect around 5 hours of sunshine a day. It is the rainy season: rain falls on about 23 days, totalling 168 mm. The air is often humid and muggy. All in all, September is a good month for a holiday in Koh Tao.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 69 | 66 | 66 |
| Day | 28° | 28° | 27° |
| Night | 26° | 26° | 26° |
| Sea | 29° | 29° | 29° |
| Sun | 6 h | 5 h | 5 h |
| Rain days | 19 | 23 | 26 |
More details for September
- Daylight
- 12 h 12 min06:10 – 18:22
- UV index
- 13 · extremeclear sky, noon (estimate)All months
- Muggy days
- 30 daysdew point 18 °C or moreAll months
- Wind
- 25 km/haverage daily peakAll months
- Cloud cover
- 89 %on averageAll months
- Hot days
- 0 days30 °C or moreAll months
- Time zone
- UTC+7Asia/Bangkok
How the score comes together
- Temperatureweight 35 %100 %
- Seaweight 25 %100 %
- Sunshineweight 20 %32 %
- Few rainy daysweight 20 %0 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in September
- Swimwear
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
- Insect repellent
- Rain jacket or umbrella
Koh Tao in September: quick answers
Is Koh Tao hot in September?
Yes. In September, Koh Tao is hot: daytime highs average 28 °C and nights stay around 26 °C.
Can you swim in Koh Tao in September?
Yes. In September the sea averages 29.1 °C – almost as warm as a bath.
Does it rain much in Koh Tao in September?
It rains often – on about 23 days, adding up to 168 mm.
Koh Tao month by month
The whole year in Koh TaoAll destinations: ThailandWhere to go in SeptemberSea temperature in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences