Climate averages 1991–2020
Niiza weather
in August.
A hot, wet month: the warmest and the 8th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
August is a hot month in Niiza: daytime highs average 29.9°C and nights cool to about 23.2°C. By daytime temperature it is the warmest month of the year.
Expect about 142 mm of rain on roughly 15 days, which makes August a wet month (the 8th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 13 h 31 min on an average August day.
The nearest other city in this atlas is Tokorozawa (8 km away). In August its highs average 29.0°C, 0.8°C cooler than Niiza, with 142 mm of rain.
Among the 303 cities listed in Japan, Niiza ranks joint 115th of 303 for the warmest August highs and joint 129th of 303 for the driest August (rainfall, lowest first). The mean August high of those 303 cities is 29.2°C; Niiza is 0.7°C warmer than that mean.
From August to September, average highs fall by 3.9°C to 26.0°C, and monthly rainfall rises from 142 mm to 204 mm.
The annual picture
August 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
Niiza climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.9°C-1.6°C | -1.6°C | 69 | 7.5 | 10.010 h |
| February | 8.9°C-0.9°C | -0.9°C | 66 | 8.5 | 10.911 h |
| March | 12.4°C2.7°C | 2.7°C | 120 | 13.2 | 11.912 h |
| April | 17.5°C7.9°C | 7.9°C | 123 | 12.8 | 13.113 h |
| May | 22.0°C13.4°C | 13.4°C | 139 | 13.1 | 14.014 h |
| June | 24.8°C17.7°C | 17.7°C | 177 | 15.4 | 14.515 h |
| July | 28.5°C21.8°C | 21.8°C | 182 | 16.4 | 14.314 h |
| August, selected | 29.9°C23.2°C | 23.2°C | 142 | 15.4 | 13.514 h |
| September | 26.0°C19.6°C | 19.6°C | 204 | 14.9 | 12.412 h |
| October | 20.5°C13.5°C | 13.5°C | 215 | 13.7 | 11.311 h |
| November | 15.3°C7.2°C | 7.2°C | 92 | 10.2 | 10.310 h |
| December | 10.3°C1.4°C | 1.4°C | 61 | 7.4 | 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
August in nearby cities
- Tokorozawa in AugustJapan · 8 kmHigh 29.0°C · Low 22.4°C · 142 mm rain
- Yono in AugustJapan · 10 kmHigh 29.9°C · Low 22.9°C · 118 mm rain
- Kawagoe in AugustJapan · 12 kmHigh 29.4°C · Low 22.6°C · 128 mm rain
- Musashino in AugustJapan · 13 kmHigh 29.2°C · Low 23.1°C · 142 mm rain
- Saitama in AugustJapan · 13 kmHigh 30.1°C · Low 23.2°C · 118 mm rain
- Sayama in AugustJapan · 14 kmHigh 29.1°C · Low 22.3°C · 142 mm rain
- Kawaguchi in AugustJapan · 14 kmHigh 30.2°C · Low 23.4°C · 110 mm rain
- Iruma in AugustJapan · 17 kmHigh 28.7°C · Low 22.2°C · 205 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 Niiza) is explained once on the Niiza year overview and on the Sources, method and limits page.
Tokorozawa, Fuchū and Hino lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.