Average annual temperature is 13.5 °C
Absolute maximum temperature: 34.5 °C
Absolute minimum temperature: -9.6 °C
Number of sunny days: 125 days
Number of rainy days: 224 days
Number of snow days: 16 days
Look at detailed online map of Koishihama
* Weather data for Koishihama 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) | 13.9 | 13.5 | 17.4 | 20.6 | 28.2 | 28.0 | 34.5 | 32.8 | 29.8 | 25.7 | 23.0 | 16.0 |
| Average daytime temperature (°C) | 4.2 | 5.1 | 12.0 | 15.9 | 18.7 | 23.0 | 28.3 | 29.5 | 26.1 | 19.5 | 14.5 | 7.8 |
| Average temperature (°C) | 0.8 | 1.1 | 7.6 | 11.5 | 15.0 | 20.2 | 24.9 | 26.8 | 23.1 | 15.3 | 10.2 | 4.2 |
| Average night temperature (°C) | -1.9 | -2.2 | 4.0 | 8.2 | 12.2 | 18.1 | 21.9 | 24.8 | 20.8 | 12.0 | 7.0 | 1.5 |
| Absolute minimum temperature (°C) | -9.6 | -9.3 | -2.1 | 3.0 | 5.4 | 14.1 | 18.0 | 23.1 | 13.9 | 5.1 | -1.4 | -3.5 |
| 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 | 14.0 | 13.0 | 11.0 | 10.0 | 9.0 |
| Daylight mean duration (h) | 9.8 | 10.7 | 12.0 | 13.2 | 14.3 | 14.9 | 14.6 | 13.7 | 12.4 | 11.2 | 10.1 | 9.5 |
| Daylight minimum duration (h) | 9.0 | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 14.0 | 13.0 | 11.0 | 10.0 | 9.0 | 9.0 |
| Sunshine mean duration (h) | 6.5 | 7.6 | 8.6 | 9.1 | 8.7 | 8.1 | 9.7 | 11.3 | 7.6 | 8.7 | 6.9 | 6.1 |
| Precipitation (mm) | 24 | 49 | 177 | 119 | 124 | 206 | 142 | 155 | 227 | 88 | 91 | 65 |
| Sunny days | 15 | 12 | 19 | 18 | 12 | 5 | 6 | 2 | 3 | 13 | 11 | 9 |
| Rainy days | 11 | 11 | 12 | 12 | 19 | 25 | 25 | 29 | 27 | 18 | 18 | 17 |
| Snow days | 5 | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 5 |
The best time to visit Koishihama during the most sunny months:
The largest precipitation sum in Koishihama is at