Hanoi weather in September
September in Hanoi: sweltering, soaked, with poor air quality — one of the weakest months to visit.
#11 of 12 months in Hanoi · #584 of 604 destinations to visit in September · comfort 44/100 (tier F)
Updated June 2026 · climate normals from ERA5 reanalysis
Hanoi climate normals — September
| Daytime high | 31°C / 87°F | 🔥 sweltering |
|---|---|---|
| Nighttime low | 25°C / 76°F | |
| Feels like (high) | 37°C / 99°F | |
| Rainfall | 259 mm / 10.2 in | ⛈ soaked |
| Rainy days | 21 days | |
| Humidity | 86% | 💦 very humid |
| Dew point | 24°C / 76°F | |
| Sunshine | 7.4 h/day | |
| Daylight | 12.3 h | |
| Wind | 11 km/h / 7 mph | |
| Air quality (US AQI) | 104 | 😷 poor |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is Hanoi?
Loading map…
Hanoi in September — FAQ
- Is September a good time to visit Hanoi?
- September in Hanoi: sweltering, soaked, with poor air quality — one of the weakest months to visit. It ranks #11 of 12 months for Hanoi on SeasonMap's comfort score (44/100).
- What is the weather like in Hanoi in September?
- In September, Hanoi averages a daily high of 30.7°C and a low of 24.5°C, with about 258.6 mm of rain over roughly 20.8 rainy days.
- What is the air quality in Hanoi in September?
- Hanoi has a mean US Air Quality Index of about 104 in September.