Climate averages 1991–2020
Jōetsu weather
in September.
A warm, wet month: the 3rd warmest and the 6th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Jōetsu: daytime highs average 25.2°C and nights cool to about 18.4°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 162 mm of rain on roughly 14 days, which makes September a wet month (the 6th 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 Kashiwazaki (37 km away). In September its highs average 25.4°C, about as warm as Jōetsu, with 163 mm of rain.
Among the 303 cities listed in Japan, Jōetsu ranks joint 210th of 303 for the warmest September highs and joint 51st of 303 for the driest September (rainfall, lowest first). The mean September high of those 303 cities is 25.7°C; Jōetsu is 0.5°C cooler than that mean.
From September to October, average highs fall by 5.6°C to 19.6°C, and monthly rainfall rises from 162 mm to 164 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
Jōetsu climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 4.1°C-1.1°C | -1.1°C | 254 | 26.0 | 9.910 h |
| February | 4.6°C-1.3°C | -1.3°C | 179 | 21.4 | 10.811 h |
| March | 8.3°C0.6°C | 0.6°C | 145 | 19.6 | 11.912 h |
| April | 15.2°C5.4°C | 5.4°C | 97 | 13.4 | 13.113 h |
| May | 21.0°C11.5°C | 11.5°C | 92 | 11.6 | 14.114 h |
| June | 24.4°C16.4°C | 16.4°C | 115 | 11.5 | 14.715 h |
| July | 27.8°C20.9°C | 20.9°C | 191 | 14.4 | 14.414 h |
| August | 29.3°C22.2°C | 22.2°C | 122 | 12.1 | 13.614 h |
| September, selected | 25.2°C18.4°C | 18.4°C | 162 | 14.1 | 12.512 h |
| October | 19.6°C12.4°C | 12.4°C | 164 | 15.1 | 11.311 h |
| November | 13.7°C6.4°C | 6.4°C | 180 | 18.5 | 10.210 h |
| December | 7.4°C1.2°C | 1.2°C | 247 | 24.2 | 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
- Kashiwazaki in SeptemberJapan · 37 kmHigh 25.4°C · Low 18.2°C · 163 mm rain
- Nagano in SeptemberJapan · 56 kmHigh 23.9°C · Low 15.9°C · 182 mm rain
- Nagaoka in SeptemberJapan · 64 kmHigh 25.6°C · Low 17.7°C · 144 mm rain
- Sanjō in SeptemberJapan · 82 kmHigh 25.4°C · Low 17.9°C · 156 mm rain
- Ueda in SeptemberJapan · 83 kmHigh 24.4°C · Low 16.2°C · 161 mm rain
- Tsubame in SeptemberJapan · 84 kmHigh 25.0°C · Low 18.6°C · 139 mm rain
- Shibukawa in SeptemberJapan · 100 kmHigh 24.4°C · Low 18.0°C · 201 mm rain
- Azumino in SeptemberJapan · 101 kmHigh 24.2°C · Low 16.3°C · 199 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 Jōetsu) is explained once on the Jōetsu year overview and on the Sources, method and limits page.