Climate averages 1991–2020
Nagano weather
in September.
A warm, very wet month: the 3rd warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Nagano: daytime highs average 23.9°C and nights cool to about 15.9°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 182 mm of rain on roughly 17 days, which makes September a very wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 27 min on an average September day.
The nearest other city in this atlas is Ueda (29 km away). In September its highs average 24.4°C, about as warm as Nagano, with 161 mm of rain.
Among the 303 cities listed in Japan, Nagano ranks 262nd of 303 for the warmest September highs and 132nd of 303 for the driest September (rainfall, lowest first). The mean September high of those 303 cities is 25.7°C; Nagano is 1.8°C cooler than that mean.
From September to October, average highs fall by 5.8°C to 18.0°C, and monthly rainfall falls from 182 mm to 161 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Nagano climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 2.1°C-4.7°C | -4.7°C | 148 | 22.8 | 10.010 h |
| February | 3.2°C-4.4°C | -4.4°C | 121 | 19.1 | 10.811 h |
| March | 7.1°C-1.5°C | -1.5°C | 138 | 18.6 | 11.912 h |
| April | 13.9°C3.2°C | 3.2°C | 115 | 14.6 | 13.113 h |
| May | 20.6°C9.7°C | 9.7°C | 133 | 14.7 | 14.114 h |
| June | 23.7°C14.7°C | 14.7°C | 178 | 18.1 | 14.615 h |
| July | 26.9°C19.0°C | 19.0°C | 243 | 21.7 | 14.414 h |
| August | 28.1°C19.9°C | 19.9°C | 169 | 19.5 | 13.614 h |
| September, selected | 23.9°C15.9°C | 15.9°C | 182 | 17.0 | 12.412 h |
| October | 18.0°C9.5°C | 9.5°C | 161 | 15.6 | 11.311 h |
| November | 12.0°C3.2°C | 3.2°C | 116 | 16.4 | 10.310 h |
| December | 5.3°C-2.3°C | -2.3°C | 138 | 20.4 | 9.710 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Ueda in SeptemberJapan · 29 kmHigh 24.4°C · Low 16.2°C · 161 mm rain
- Azumino in SeptemberJapan · 48 kmHigh 24.2°C · Low 16.3°C · 199 mm rain
- Matsumoto in SeptemberJapan · 50 kmHigh 24.3°C · Low 16.2°C · 199 mm rain
- Saku in SeptemberJapan · 55 kmHigh 23.7°C · Low 16.4°C · 187 mm rain
- Jōetsu in SeptemberJapan · 56 kmHigh 25.2°C · Low 18.4°C · 162 mm rain
- Shibukawa in SeptemberJapan · 75 kmHigh 24.4°C · Low 18.0°C · 201 mm rain
- Takasaki in SeptemberJapan · 82 kmHigh 24.1°C · Low 17.5°C · 257 mm rain
- Maebashi in SeptemberJapan · 85 kmHigh 24.5°C · Low 17.9°C · 201 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Nagano) is explained once on the Nagano year overview and on the Sources, method and limits page.