SeasonMapKo Pha Ngan (Koh Phangan) weather in September
Thailand
September in Ko Pha Ngan: sweltering, soaked, with clean air — fine if you can take 22 rainy days.
#10 of 12 months in Ko Pha Ngan · #933 of 1383 destinations to visit in September · comfort 70/100 (tier B)
Updated September 2026 · climate normals from ERA5 reanalysis
Traveller notes on Ko Pha Ngan in September
Other months in Ko Pha Ngan
Ko Pha Ngan's forum puts March close to the neighbouring months either side — regulars comparing February and April describe similar humidity with only a degree or two of difference, which puts March comfortably in the middle. Expect warm, humid days typical of the island's dry-ish season, with the occasional shower rather than sustained rain.
Add your own note from Ko Pha Ngan's card on the map.
Ko Pha Ngan climate normals — September
| Daytime high | 30°C / 86°F | 🔥 sweltering |
|---|---|---|
| Nighttime low | 26°C / 79°F | |
| Feels like (high) | 35°C / 95°F | |
| Sea temperature | 30°C / 86°F | ♨️ bath-warm |
| Rainfall | 180 mm / 7.1 in | ⛈ soaked |
| Rainy days | 22 days | |
| Humidity | 81% | 💦 very humid |
| Dew point | 24°C / 76°F | |
| Sunshine | 8.6 h/day | |
| Daylight | 12.2 h | |
| Wind | 25 km/h / 16 mph | |
| Air quality (US AQI) | 27 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Ko Pha Ngan in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
BusyFull Moon Party, school holidays in 3 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Ko Pha Ngan's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Toughest weatherKo Pha Ngan's weather peaks January–March.
Best weatherFair weatherToughest weather
What's on in Ko Pha Ngan in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Festival
Full Moon Party
1 Jan – 31 DecMajor festivalCrowdedBook earlyHaad Rin fills once a lunar month, every month, and the island's boats and rooms price around it. Arrive two days either side and it is a different, much quieter island. Source ↗
Nearby, and something's on
Within 300 km of Ko Pha Ngan — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Ko Pha Ngan?
Ko Pha Ngan in September — FAQ
- Is September a good time to visit Ko Pha Ngan?
- September in Ko Pha Ngan: sweltering, soaked, with clean air — fine if you can take 22 rainy days. It ranks #10 of 12 months for Ko Pha Ngan on SeasonMap's comfort score (70/100).
- What is the weather like in Ko Pha Ngan in September?
- In September, Ko Pha Ngan averages a daily high of 30.1°C and a low of 25.9°C, with about 179.9 mm of rain over roughly 22.2 rainy days.
- What is the air quality in Ko Pha Ngan in September?
- Ko Pha Ngan has a mean US Air Quality Index of about 27 in September.
Other months in Ko Pha Ngan
Compare Ko Pha Ngan in September
Warmer or cooler than Ko Pha Ngan in September
Similar destinations in Southeast Asia — September
Within 300 km: Ko Tao's Clear water, dive season around 1 Feb – 30 Sep, and Khao Sok's Southwest monsoon around 1 May – 30 Sep.