Average annual temperature is 15.4 °C
Absolute maximum temperature: 35.6 °C
Absolute minimum temperature: -10.7 °C
Number of sunny days: 156 days
Number of rainy days: 204 days
Number of snow days: 5 days
Look at detailed online map of Koyama
* Weather data for Koyama 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) | 15.2 | 15.5 | 22.7 | 24.7 | 27.1 | 29.3 | 34.6 | 35.6 | 32.3 | 26.0 | 25.5 | 18.6 |
| Average daytime temperature (°C) | 7.9 | 8.8 | 15.7 | 18.6 | 22.2 | 25.3 | 30.8 | 32.2 | 29.7 | 21.2 | 16.4 | 11.3 |
| Average temperature (°C) | 3.0 | 4.4 | 10.1 | 13.4 | 17.5 | 21.5 | 26.6 | 28.0 | 25.3 | 16.4 | 11.9 | 6.5 |
| Average night temperature (°C) | -1.5 | 0.5 | 5.4 | 8.7 | 13.3 | 18.1 | 23.0 | 24.7 | 21.8 | 12.4 | 8.3 | 2.3 |
| Absolute minimum temperature (°C) | -10.7 | -4.0 | -1.5 | 2.2 | 6.3 | 10.7 | 20.3 | 22.8 | 17.8 | 7.5 | 1.3 | -3.7 |
| 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 | 14.2 | 13.4 | 12.4 | 11.3 | 10.3 | 9.9 |
| Daylight minimum duration (h) | 9.0 | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 13.0 | 12.0 | 11.0 | 10.0 | 10.0 | 9.0 |
| Sunshine mean duration (h) | 6.9 | 5.9 | 8.5 | 7.9 | 9.4 | 6.6 | 9.8 | 10.0 | 9.7 | 8.7 | 7.3 | 6.9 |
| Precipitation (mm) | 44 | 48 | 121 | 174 | 229 | 328 | 119 | 182 | 96 | 49 | 100 | 48 |
| Sunny days | 9 | 12 | 19 | 15 | 15 | 9 | 11 | 6 | 7 | 15 | 17 | 21 |
| Rainy days | 19 | 14 | 12 | 15 | 16 | 21 | 20 | 25 | 23 | 16 | 13 | 10 |
| Snow days | 3 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
The largest precipitation sum in Koyama is at