Nagasaki weather in September
September in Nagasaki: warm, soaked, with clean air — fine if you can take 13 rainy days.
#9 of 12 months in Nagasaki · #745 of 897 destinations to visit in September · comfort 65/100 (tier C)
Updated June 2026 · climate normals from ERA5 reanalysis
Traveller notes on Nagasaki in September
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Nagasaki climate normals — September
| Daytime high | 27°C / 81°F | 🌤 warm |
|---|---|---|
| Nighttime low | 24°C / 75°F | |
| Rainfall | 176 mm / 6.9 in | ⛈ soaked |
| Rainy days | 13 days | |
| Humidity | 80% | 💦 very humid |
| Dew point | 22°C / 72°F | |
| Sunshine | 8.8 h/day | |
| Daylight | 12.4 h | |
| Wind | 22 km/h / 13 mph | |
| Air quality (US AQI) | 50 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Nagasaki in September — FAQ
- Is September a good time to visit Nagasaki?
- September in Nagasaki: warm, soaked, with clean air — fine if you can take 13 rainy days. It ranks #9 of 12 months for Nagasaki on SeasonMap's comfort score (65/100).
- What is the weather like in Nagasaki in September?
- In September, Nagasaki averages a daily high of 27.4°C and a low of 23.7°C, with about 175.6 mm of rain over roughly 12.6 rainy days.
- What is the air quality in Nagasaki in September?
- Nagasaki has a mean US Air Quality Index of about 50 in September.