Climate averages 1991–2020
Oyama 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 Oyama: daytime highs average 25.7°C and nights cool to about 18.9°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 206 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 27 min on an average September day.
The nearest other city in this atlas is Tochigi (11 km away). In September its highs average 25.5°C, about as warm as Oyama, with 239 mm of rain.
Among the 303 cities listed in Japan, Oyama ranks joint 182nd of 303 for the warmest September highs and joint 218th of 303 for the driest September (rainfall, lowest first). The mean September high of those 303 cities is 25.7°C; Oyama is level with that mean.
From September to October, average highs fall by 5.5°C to 20.2°C, and monthly rainfall falls from 206 mm to 200 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
Oyama climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.3°C-2.1°C | -2.1°C | 55 | 6.0 | 10.010 h |
| February | 8.4°C-1.5°C | -1.5°C | 55 | 6.9 | 10.811 h |
| March | 12.2°C1.6°C | 1.6°C | 106 | 11.6 | 11.912 h |
| April | 17.4°C6.8°C | 6.8°C | 120 | 12.6 | 13.113 h |
| May | 22.1°C12.4°C | 12.4°C | 153 | 13.7 | 14.114 h |
| June | 24.7°C16.9°C | 16.9°C | 177 | 16.5 | 14.615 h |
| July | 28.2°C21.0°C | 21.0°C | 209 | 18.7 | 14.414 h |
| August | 29.5°C22.3°C | 22.3°C | 161 | 16.3 | 13.514 h |
| September, selected | 25.7°C18.9°C | 18.9°C | 206 | 16.2 | 12.412 h |
| October | 20.2°C12.7°C | 12.7°C | 200 | 13.9 | 11.311 h |
| November | 14.9°C5.9°C | 5.9°C | 88 | 9.4 | 10.310 h |
| December | 9.7°C0.4°C | 0.4°C | 54 | 6.8 | 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
- Tochigi in SeptemberJapan · 11 kmHigh 25.5°C · Low 18.8°C · 239 mm rain
- Koga in SeptemberJapan · 15 kmHigh 26.0°C · Low 19.2°C · 206 mm rain
- Chikusei in SeptemberJapan · 16 kmHigh 26.1°C · Low 19.1°C · 164 mm rain
- Sano in SeptemberJapan · 20 kmHigh 25.7°C · Low 18.9°C · 221 mm rain
- Mooka in SeptemberJapan · 24 kmHigh 25.8°C · Low 18.5°C · 165 mm rain
- Tatebayashi in SeptemberJapan · 25 kmHigh 25.7°C · Low 18.9°C · 221 mm rain
- Kazo in SeptemberJapan · 27 kmHigh 26.1°C · Low 19.3°C · 186 mm rain
- Kukichūō in SeptemberJapan · 28 kmHigh 26.2°C · Low 19.4°C · 171 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 Oyama) is explained once on the Oyama year overview and on the Sources, method and limits page.
Koga lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.