Average annual temperature is 16.4 °C
Absolute maximum temperature: 33.8 °C
Absolute minimum temperature: -4.4 °C
Number of sunny days: 154 days
Number of rainy days: 211 days
Look at detailed online map of Koiwaya
* Weather data for Koiwaya 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) | 20.1 | 19.4 | 23.3 | 24.6 | 31.7 | 31.1 | 32.6 | 33.8 | 32.5 | 26.3 | 25.5 | 21.7 |
| Average daytime temperature (°C) | 11.2 | 13.3 | 17.6 | 19.9 | 23.9 | 25.9 | 30.2 | 29.1 | 29.7 | 22.9 | 18.6 | 13.5 |
| Average temperature (°C) | 5.9 | 8.1 | 12.2 | 14.8 | 18.6 | 21.7 | 25.8 | 25.4 | 24.7 | 17.2 | 13.0 | 8.3 |
| Average night temperature (°C) | 2.0 | 4.1 | 7.8 | 10.7 | 14.4 | 18.4 | 22.9 | 22.7 | 21.2 | 12.8 | 9.1 | 4.5 |
| Absolute minimum temperature (°C) | -4.4 | -1.8 | -0.8 | 3.5 | 8.3 | 14.8 | 21.0 | 20.8 | 19.6 | 8.1 | 2.7 | -2.6 |
| 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 | 10.0 |
| Daylight mean duration (h) | 10.3 | 11.1 | 12.0 | 13.0 | 13.8 | 14.2 | 14.0 | 13.3 | 12.4 | 11.4 | 10.5 | 10.1 |
| Daylight minimum duration (h) | 10.0 | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 13.0 | 12.0 | 11.0 | 10.0 | 10.0 | 10.0 |
| Sunshine mean duration (h) | 7.4 | 6.7 | 7.7 | 7.7 | 8.4 | 6.1 | 9.1 | 8.2 | 10.0 | 8.5 | 8.7 | 7.1 |
| Precipitation (mm) | 84 | 163 | 171 | 203 | 199 | 513 | 207 | 479 | 54 | 59 | 40 | 106 |
| Sunny days | 21 | 16 | 16 | 10 | 13 | 7 | 0 | 3 | 4 | 21 | 21 | 22 |
| Rainy days | 10 | 12 | 15 | 20 | 18 | 23 | 31 | 28 | 26 | 10 | 9 | 9 |
| Snow days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
The largest precipitation sum in Koiwaya is at