Climate Insights for Jämsä

The climate in Jämsä is cool. The average annual temperature is 5°C and approximately 730mm of precipitation falls per year. Jämsä receives a notable amount of rainfall throughout the year, including during its driest month. Jämsä is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, June, August. The coldest months are January, February, March, when temperatures can drop to -8°C. Jämsä experiences heavy snowfall, typically from January through December.

Temperatures in Jämsä vary considerably across the year, with a 29°C difference between the coldest and warmest months. July is the warmest month, though highs remain moderate at 21°C with a mean of 18°C. The coldest month is January, when overnight lows fall to -8°C and the daily average is -6°C. Daily temperature variation is modest, with an average difference of 7°C between highs and lows. The sharpest temperature change occurs between April and May, with a 7°C shift in average temperatures.

Jämsä is a relatively dry area, receiving approximately 730mm of precipitation annually, which averages out to around 61mm per month. The wettest month is August, averaging 93mm of rainfall. July and October also tend to see above-average precipitation. The driest month is March, with just 38mm. That's 55mm less than August, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around. Jämsä receives heavy snowfall, accumulating around 205cm annually from January through December. The snowiest month is December, with approximately 46cm. Winter travel should account for significant snow cover.

Jämsä is mildly breezy, with an average annual wind speed of 12km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is October, averaging 14km/h, though still comfortable for most outdoor activities. The calmest conditions occur in May, with average winds dropping to 10km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 4km/h between the calmest and windiest months. Wind tends to be stronger during winter months, driven by seasonal pressure systems. The seasonal averages break down to 14km/h in winter, 12km/h in spring, 11km/h in summer, 13km/h in autumn.

It is currently autumn in Jämsä, which began on September 23, 2026. Jämsä is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in July at around 21°C, while the coldest stretch bottoms out in January near -8°C. Winter is next, beginning on December 21, 2026 (88 days from now).

The best time to visit Jämsä is during June, July and August, when the weather is most comfortable for travellers. During these months, average temperatures hover around 16°C with modest rainfall averaging 82mm per month. By contrast, January can be quite cold with temperatures dropping to -8°C. Despite being the best months overall, some rain is still likely. Pack a waterproof layer and plan a mix of indoor and outdoor activities.

The table below shows monthly climate averages for Jämsä based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.