Average annual temperature is 3.4 °C
Absolute maximum temperature: 28.9 °C
Absolute minimum temperature: -23.1 °C
Number of sunny days: 139 days
Number of rainy days: 142 days
Number of snow days: 84 days
Look at detailed online map of Iso-Jämsä
* Weather data for Iso-Jämsä Finland is based on climate observations for 2026 year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Absolute maximum temperature (°C) | 4.7 | 4.0 | 2.0 | 13.9 | 20.9 | 26.0 | 24.7 | 28.9 | 20.6 | 10.7 | 3.8 | 2.6 |
| Average daytime temperature (°C) | -2.0 | -2.8 | -3.6 | 5.4 | 11.4 | 18.2 | 19.0 | 20.1 | 15.2 | 2.8 | -2.5 | -5.4 |
| Average temperature (°C) | -3.9 | -5.2 | -6.9 | 0.4 | 7.3 | 14.7 | 15.7 | 16.5 | 12.6 | 0.5 | -4.5 | -7.3 |
| Average night temperature (°C) | -6.1 | -7.7 | -10.7 | -3.9 | 3.0 | 10.1 | 11.8 | 12.9 | 9.6 | -1.9 | -7.0 | -9.6 |
| Absolute minimum temperature (°C) | -18.1 | -16.9 | -23.1 | -11.9 | -3.8 | 3.1 | 8.4 | 7.6 | 0.3 | -11.9 | -16.2 | -16.5 |
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight maximum duration (h) | 6.0 | 9.0 | 13.0 | 16.0 | 20.0 | 22.0 | 21.0 | 18.0 | 14.0 | 11.0 | 7.0 | 4.0 |
| Daylight mean duration (h) | 5.1 | 8.4 | 11.8 | 15.3 | 18.9 | 21.9 | 20.2 | 16.6 | 13.1 | 9.6 | 6.2 | 3.8 |
| Daylight minimum duration (h) | 3.0 | 6.0 | 10.0 | 13.0 | 17.0 | 20.0 | 18.0 | 14.0 | 11.0 | 7.0 | 4.0 | 3.0 |
| Sunshine mean duration (h) | 0.8 | 2.0 | 6.6 | 10.6 | 13.1 | 15.3 | 11.8 | 10.7 | 6.4 | 4.0 | 0.8 | 0.1 |
| Precipitation (mm) | 65 | 25 | 37 | 42 | 52 | 51 | 116 | 112 | 133 | 99 | 41 | 35 |
| Sunny days | 11 | 11 | 11 | 20 | 16 | 15 | 6 | 9 | 5 | 13 | 14 | 8 |
| Rainy days | 9 | 4 | 1 | 5 | 12 | 15 | 25 | 22 | 25 | 13 | 6 | 5 |
| Snow days | 11 | 13 | 19 | 5 | 3 | 0 | 0 | 0 | 0 | 5 | 10 | 18 |
The best time to visit Iso-Jämsä during the most sunny months:
Months with the longest average daylight duration in Iso-Jämsä:
The largest precipitation sum in Iso-Jämsä is at