Thailand in September: where is it warmest?
In September, Bangkok is the warmest place with 31 °C by day, Ko Pha-ngan the coolest with 26 °C. 10 of 12 destinations have good holiday weather.
All destinations in September, warmest first
Long-term averages for the month: daytime high, sea, sunshine and rainy days.
| Place | Score | Air | Sea | Sun | Rain days |
|---|---|---|---|---|---|
| Bangkok | 30 | 31° | – | 4 h | 25 |
| Pattaya | 66 | 30° | 29° | 5 h | 21 |
| Hua Hin | 66 | 30° | 29° | 5 h | 24 |
| Koh Samui | 67 | 29° | 29° | 5 h | 25 |
| Chiang Mai | 42 | 29° | – | 5 h | 24 |
| Koh Tao | 66 | 28° | 29° | 5 h | 23 |
| Patong, Phuket | 65 | 28° | 29° | 4 h | 26 |
| Ao Nang, Krabi | 65 | 28° | 29° | 4 h | 26 |
| Khao Lak | 65 | 28° | 29° | 4 h | 26 |
| Phuket | 65 | 28° | 29° | 4 h | 26 |
| Koh Lanta | 65 | 28° | 29° | 5 h | 26 |
| Ko Pha-ngan | 67 | 26° | 29° | 5 h | 23 |
Thailand in September: quick answers
Thailand in September: where is it warmest?
The warmest places in September are Bangkok (31 °C), Pattaya (30 °C) and Hua Hin (30 °C).
Thailand in September: where is the sea warmest?
The sea is warmest at Pattaya (29 °C), Hua Hin (29 °C) and Koh Samui (29 °C).
Thailand in September: where is the weather best?
The best holiday weather in September – warm, sunny and dry – is in Koh Samui, Ko Pha-ngan and Pattaya.
Thailand month by month
Thailand: weather & best time to visit
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