Climate averages 1991–2020
Aihara 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 Aihara: daytime highs average 24.9°C and nights cool to about 18.8°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 229 mm of rain on roughly 16 days, which makes September a very wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 26 min on an average September day.
The nearest other city in this atlas is Hachiōji (6 km away). In September its highs average 25.0°C, about as warm as Aihara, with 249 mm of rain.
Among the 303 cities listed in Japan, Aihara ranks joint 232nd of 303 for the warmest September highs and joint 252nd of 303 for the driest September (rainfall, lowest first). The mean September high of those 303 cities is 25.7°C; Aihara is 0.8°C cooler than that mean.
From September to October, average highs fall by 5.2°C to 19.7°C, and monthly rainfall rises from 229 mm to 231 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
Aihara climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.7°C-1.8°C | -1.8°C | 82 | 8.4 | 10.010 h |
| February | 8.4°C-1.3°C | -1.3°C | 85 | 10.2 | 10.911 h |
| March | 11.8°C2.2°C | 2.2°C | 154 | 15.4 | 11.912 h |
| April | 16.7°C7.4°C | 7.4°C | 147 | 14.4 | 13.113 h |
| May | 20.9°C12.6°C | 12.6°C | 158 | 13.6 | 14.014 h |
| June | 23.6°C16.9°C | 16.9°C | 203 | 16.4 | 14.515 h |
| July | 27.3°C21.1°C | 21.1°C | 205 | 17.4 | 14.314 h |
| August | 28.4°C22.2°C | 22.2°C | 160 | 16.3 | 13.514 h |
| September, selected | 24.9°C18.8°C | 18.8°C | 229 | 16.1 | 12.412 h |
| October | 19.7°C13.0°C | 13.0°C | 231 | 14.5 | 11.311 h |
| November | 14.9°C7.0°C | 7.0°C | 110 | 11.7 | 10.310 h |
| December | 10.2°C1.3°C | 1.3°C | 76 | 8.8 | 9.810 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
- Hachiōji in SeptemberJapan · 6 kmHigh 25.0°C · Low 18.7°C · 249 mm rain
- Sagamihara in SeptemberJapan · 8 kmHigh 25.0°C · Low 18.9°C · 229 mm rain
- Hino in SeptemberJapan · 11 kmHigh 25.1°C · Low 19.0°C · 204 mm rain
- Machida in SeptemberJapan · 14 kmHigh 24.5°C · Low 19.5°C · 193 mm rain
- Tama in SeptemberJapan · 15 kmHigh 24.7°C · Low 19.2°C · 204 mm rain
- Akiruno in SeptemberJapan · 16 kmHigh 25.3°C · Low 19.0°C · 249 mm rain
- Minamirinkan in SeptemberJapan · 16 kmHigh 24.8°C · Low 19.5°C · 193 mm rain
- Fuchū in SeptemberJapan · 17 kmHigh 25.3°C · Low 19.4°C · 204 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 Aihara) is explained once on the Aihara year overview and on the Sources, method and limits page.
Sagamihara, Atsugi and Isehara lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.