Phnom Penh weather in September
September in Phnom Penh: sweltering, soaked, with clean air — a fair time to visit.
#12 of 12 months in Phnom Penh · #565 of 604 destinations to visit in September · comfort 51/100 (tier D)
Updated June 2026 · climate normals from ERA5 reanalysis
Phnom Penh climate normals — September
| Daytime high | 31°C / 87°F | 🔥 sweltering |
|---|---|---|
| Nighttime low | 25°C / 76°F | |
| Feels like (high) | 36°C / 97°F | |
| Rainfall | 248 mm / 9.8 in | ⛈ soaked |
| Rainy days | 27 days | |
| Humidity | 86% | 💦 very humid |
| Dew point | 24°C / 76°F | |
| Sunshine | 7.8 h/day | |
| Daylight | 12.2 h | |
| Wind | 12 km/h / 8 mph | |
| Air quality (US AQI) | 41 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Phnom Penh in September — FAQ
- Is September a good time to visit Phnom Penh?
- September in Phnom Penh: sweltering, soaked, with clean air — a fair time to visit. It ranks #12 of 12 months for Phnom Penh on SeasonMap's comfort score (51/100).
- What is the weather like in Phnom Penh in September?
- In September, Phnom Penh averages a daily high of 30.7°C and a low of 24.7°C, with about 247.7 mm of rain over roughly 27.4 rainy days.
- What is the air quality in Phnom Penh in September?
- Phnom Penh has a mean US Air Quality Index of about 41 in September.