Average annual temperature is 12.5 °C
Absolute maximum temperature: 30.4 °C
Absolute minimum temperature: -10.8 °C
Number of sunny days: 163 days
Number of rainy days: 189 days
Number of snow days: 13 days
Look at detailed online map of Ōiso-koiso
* Weather data for Ōiso-koiso Japan is based on climate observations for 2026 year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Absolute maximum temperature (°C) | 11.7 | 13.1 | 20.1 | 22.4 | 25.6 | 26.8 | 30.4 | 29.5 | 28.4 | 24.2 | 21.3 | 17.0 |
| Average daytime temperature (°C) | 6.2 | 7.2 | 12.1 | 15.5 | 18.1 | 21.8 | 27.2 | 27.3 | 25.2 | 17.2 | 14.1 | 9.6 |
| Average temperature (°C) | 1.6 | 3.0 | 7.7 | 10.6 | 13.9 | 18.1 | 22.8 | 23.1 | 21.2 | 13.1 | 9.7 | 5.3 |
| Average night temperature (°C) | -1.7 | 0.0 | 4.2 | 6.5 | 10.4 | 15.3 | 19.3 | 20.0 | 18.3 | 9.6 | 6.2 | 1.9 |
| Absolute minimum temperature (°C) | -10.8 | -5.1 | -4.2 | -3.1 | 4.0 | 11.8 | 16.1 | 17.8 | 11.6 | 5.3 | 0.0 | -4.7 |
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight maximum duration (h) | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 14.0 | 14.0 | 13.0 | 12.0 | 11.0 | 10.0 | 9.0 |
| Daylight mean duration (h) | 10.1 | 10.9 | 12.0 | 13.1 | 14.0 | 14.5 | 14.3 | 13.5 | 12.4 | 11.3 | 10.3 | 9.8 |
| Daylight minimum duration (h) | 9.0 | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 13.0 | 12.0 | 11.0 | 10.0 | 9.0 | 9.0 |
| Sunshine mean duration (h) | 7.4 | 7.5 | 8.4 | 8.9 | 9.0 | 7.5 | 9.9 | 10.6 | 9.5 | 9.0 | 7.8 | 7.6 |
| Precipitation (mm) | 53 | 124 | 179 | 148 | 245 | 417 | 96 | 184 | 180 | 99 | 80 | 61 |
| Sunny days | 14 | 16 | 16 | 14 | 12 | 7 | 7 | 4 | 13 | 18 | 20 | 22 |
| Rainy days | 8 | 9 | 15 | 16 | 19 | 23 | 24 | 27 | 17 | 13 | 10 | 8 |
| Snow days | 9 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
The largest precipitation sum in Ōiso-koiso is at