Climate averages 1991–2020
Iruma weather
in July.
A warm, very wet month: the 2nd warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
July is a warm month in Iruma: daytime highs average 27.5°C and nights cool to about 20.9°C. By daytime temperature it is the 2nd warmest of the 12 months.
Expect about 243 mm of rain on roughly 22 days, which makes July a very wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 20 min on an average July day.
The nearest other city in this atlas is Sayama (6 km away). In July its highs average 27.9°C, about as warm as Iruma, with 182 mm of rain.
Among the 303 cities listed in Japan, Iruma ranks joint 203rd of 303 for the warmest July highs and joint 219th of 303 for the driest July (rainfall, lowest first). The mean July high of those 303 cities is 27.9°C; Iruma is 0.3°C cooler than that mean.
From July to August, average highs rise by 1.2°C to 28.7°C, and monthly rainfall falls from 243 mm to 205 mm.
The annual picture
July 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
Iruma climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.2°C-2.7°C | -2.7°C | 77 | 8.5 | 10.010 h |
| February | 8.1°C-2.0°C | -2.0°C | 76 | 9.7 | 10.911 h |
| March | 11.7°C1.5°C | 1.5°C | 139 | 15.2 | 11.912 h |
| April | 16.8°C6.8°C | 6.8°C | 146 | 14.6 | 13.113 h |
| May | 21.2°C12.3°C | 12.3°C | 166 | 15.6 | 14.014 h |
| June | 23.8°C16.7°C | 16.7°C | 222 | 19.5 | 14.515 h |
| July, selected | 27.5°C20.9°C | 20.9°C | 243 | 21.8 | 14.314 h |
| August | 28.7°C22.2°C | 22.2°C | 205 | 21.0 | 13.514 h |
| September | 25.0°C18.6°C | 18.6°C | 249 | 18.2 | 12.412 h |
| October | 19.6°C12.6°C | 12.6°C | 242 | 16.2 | 11.311 h |
| November | 14.6°C6.3°C | 6.3°C | 101 | 11.3 | 10.310 h |
| December | 9.7°C0.4°C | 0.4°C | 68 | 8.3 | 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
July in nearby cities
- Sayama in JulyJapan · 6 kmHigh 27.9°C · Low 21.1°C · 182 mm rain
- Hannō in JulyJapan · 6 kmHigh 28.1°C · Low 21.5°C · 243 mm rain
- Tokorozawa in JulyJapan · 9 kmHigh 27.7°C · Low 21.2°C · 182 mm rain
- Ōme in JulyJapan · 12 kmHigh 28.0°C · Low 21.4°C · 243 mm rain
- Kawagoe in JulyJapan · 15 kmHigh 28.1°C · Low 21.3°C · 170 mm rain
- Sakado in JulyJapan · 16 kmHigh 28.3°C · Low 21.5°C · 170 mm rain
- Akiruno in JulyJapan · 16 kmHigh 27.9°C · Low 21.3°C · 243 mm rain
- Hino in JulyJapan · 16 kmHigh 27.5°C · Low 21.2°C · 182 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 Iruma) is explained once on the Iruma year overview and on the Sources, method and limits page.
Hachiōji, Ōme and Akiruno lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.