SeasonMapNagano weather in September
Japan
September in Nagano: warm, soaked, with clean air — fine if you can take 18 rainy days.
#3 of 12 months in Nagano · #836 of 1383 destinations to visit in September · comfort 76/100 (tier B)
Updated September 2026 · climate normals from ERA5 reanalysis
Traveller notes on Nagano in September
No notes yet. Open Nagano on the map to add the first one.
Nagano climate normals — September
| Daytime high | 25°C / 77°F | 🌤 warm |
|---|---|---|
| Nighttime low | 17°C / 63°F | |
| Rainfall | 186 mm / 7.3 in | ⛈ soaked |
| Rainy days | 18 days | |
| Humidity | 86% | 💦 very humid |
| Dew point | 19°C / 65°F | |
| Sunshine | 8.4 h/day | |
| Daylight | 12.4 h | |
| Wind | 9 km/h / 5 mph | |
| Air quality (US AQI) | 33 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Nagano 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.
Busyschool holidays in 3 of the markets that fill it, one of its best months for weather(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Nagano'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).
Best weatherNagano's best weather comes in May, June and September — separate windows, not one continuous season.
Best weatherFair weatherToughest weather
Nearby, and something's on
Within 300 km of Nagano — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Nagano?
Nagano in September — FAQ
- Is September a good time to visit Nagano?
- September in Nagano: warm, soaked, with clean air — fine if you can take 18 rainy days. It ranks #3 of 12 months for Nagano on SeasonMap's comfort score (76/100).
- What is the weather like in Nagano in September?
- In September, Nagano averages a daily high of 25.2°C and a low of 17.3°C, with about 185.6 mm of rain over roughly 18.2 rainy days.
- What is the air quality in Nagano in September?
- Nagano has a mean US Air Quality Index of about 33 in September.
Other months in Nagano
Compare Nagano in September
Warmer or cooler than Nagano in September
Similar destinations in East Asia — September
Within 300 km: Hakuba's High trails and huts open around 1 Jul – 15 Oct, and Matsumoto's Kamikochi open season around 17 Apr – 15 Nov.