Average annual temperature is 15.4 °C
Absolute maximum temperature: 33.4 °C
Absolute minimum temperature: -6.5 °C
Number of sunny days: 143 days
Number of rainy days: 215 days
Number of snow days: 7 days
Look at detailed online map of Koyasu
* Weather data for Koyasu 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) | 14.2 | 17.4 | 21.7 | 22.8 | 28.2 | 29.4 | 33.4 | 33.2 | 31.8 | 25.7 | 24.0 | 21.0 |
| Average daytime temperature (°C) | 7.9 | 9.5 | 14.7 | 18.3 | 20.7 | 24.6 | 30.1 | 30.4 | 28.2 | 20.6 | 16.9 | 11.7 |
| Average temperature (°C) | 3.7 | 5.0 | 10.7 | 13.9 | 16.8 | 21.2 | 26.0 | 26.4 | 24.3 | 16.4 | 12.2 | 7.3 |
| Average night temperature (°C) | 0.3 | 1.5 | 7.3 | 10.1 | 13.4 | 18.5 | 22.6 | 23.3 | 21.5 | 12.8 | 8.7 | 3.6 |
| Absolute minimum temperature (°C) | -6.5 | -3.5 | -0.3 | 4.2 | 7.7 | 15.2 | 19.3 | 21.7 | 16.3 | 7.9 | 2.3 | -3.1 |
| 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) | 7.0 | 7.1 | 7.9 | 8.5 | 8.5 | 7.1 | 9.9 | 10.9 | 9.0 | 8.6 | 7.3 | 7.6 |
| Precipitation (mm) | 35 | 78 | 175 | 170 | 236 | 407 | 86 | 233 | 218 | 150 | 76 | 65 |
| Sunny days | 14 | 13 | 14 | 11 | 11 | 4 | 15 | 3 | 8 | 14 | 15 | 21 |
| Rainy days | 13 | 12 | 17 | 19 | 20 | 26 | 16 | 28 | 22 | 17 | 15 | 10 |
| Snow days | 4 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
The best time to visit Koyasu during the most sunny months:
The largest precipitation sum in Koyasu is at