Koh Lanta 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: January – March
What is the weather like in Koh Lanta in September?
In September, Koh Lanta is hot: daytime highs average 28 °C, and even at night it stays warm at around 25 °C. The sea averages 29.4 °C – almost as warm as a bath. Expect around 5 hours of sunshine a day. It is the rainy season: rain falls on about 26 days, totalling 300 mm. The air is often humid and muggy. All in all, September is a good month for a holiday in Koh Lanta.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 67 | 65 | 64 |
| Day | 28° | 28° | 28° |
| Night | 26° | 25° | 25° |
| Sea | 30° | 29° | 29° |
| Sun | 5 h | 5 h | 4 h |
| Rain days | 25 | 26 | 28 |
More details for September
- Daylight
- 12 h 10 min06:14 – 18:24
- UV index
- 14 · extremeclear sky, noon (estimate)All months
- Muggy days
- 30 daysdew point 18 °C or moreAll months
- Wind
- 14 km/haverage daily peakAll months
- Cloud cover
- 88 %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 %27 %
- 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 Lanta in September: quick answers
Is Koh Lanta hot in September?
Yes. In September, Koh Lanta is hot: daytime highs average 28 °C and nights stay around 25 °C.
Can you swim in Koh Lanta in September?
Yes. In September the sea averages 29.4 °C – almost as warm as a bath.
Does it rain much in Koh Lanta in September?
It rains often – on about 26 days, adding up to 300 mm.
Koh Lanta month by month
The whole year in Koh LantaAll 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