Jämsä climate — normals and trends
Jämsä (Finland) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 4.0 °C and it receives 633 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (16.9 °C on average) and the coldest is January (-7.9 °C). Rainfall peaks in August.
Jämsä averages 160 frost days, 1 hot days (≥ 30 °C) and 132 rainy days per year.
Jämsä has warmed by +2.4 °C between 1940 and 2025, or +0.28 °C per decade. This trend is statistically significant.
The number of frost days there went from about 175 to 145 per year over the period.
The hottest day of the period reached 33.4 °C (on 29 July 2010) and the coldest -37.5 °C (on 8 January 1987).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
JämsäCentral Finland
- coords
- 61.86°, 25.19°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
4.0°C
Average daily high
7.0°C
Average daily low
0.9°C
Annual rainfall
633mm
Sunshine / day
6.7h
Mean relative humidity
82%
Average peak wind
16.6km/h
Seasonal range
24.8°C
Frost days (< 0 °C)
160 d/yr
Hot days (≥ 30 °C)
1 d/yr
Rainy days (≥ 1 mm)
132 d/yr
Annual snowfall
135.5 cm
Average feels-like high
3.8 °C
Average feels-like low
-2.8 °C
Average peak gust
34.5 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
8.8 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.4 °C
since 1940
+0.3 °C per decade · r² = 0.33 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
33.4 °C
29 July 2010
Coldest day
-37.5 °C
8 January 1987
Wettest day
72 mm
12 August 1972
Windiest day
44.4 km/h
23 January 1995
Strongest gust
95.8 km/h
26 October 1985
Hottest feels-like
34.8 °C
8 August 2010
Coldest feels-like
-42.6 °C
8 January 1987
Snowiest day
19.6 cm
25 January 2002
Sunniest day
18.9 h
21 June 2012
Normals computed over complete calendar years 1940–2025.
A specific year
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Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | -1.0 °C | +4.5 °C | 49 mm | +10 mm |
| Feb | -2.1 °C | +3.2 °C | 20 mm | -11 mm |
| Mar | 4.1 °C | +4.6 °C | 36 mm | +4 mm |
| Apr | 9.1 °C | +3.4 °C | 44 mm | +6 mm |
| May | 12.8 °C | -0.7 °C | 35 mm | -7 mm |
| Jun | 17.6 °C | -0.9 °C | 121 mm | +61 mm |
| Jul | 24.7 °C | +4.0 °C | 61 mm | -18 mm |
| Aug | 18.9 °C | +0.1 °C | 97 mm | +10 mm |
| Sep | 16.4 °C | +3.3 °C | 87 mm | +23 mm |
| Oct | 8.4 °C | +1.5 °C | 59 mm | -2 mm |
| Nov | 4.5 °C | +3.2 °C | 55 mm | +1 mm |
| Dec | 2.1 °C | +4.9 °C | 69 mm | +22 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Jämsä?
Jämsä has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 4.0 °C and it receives 633 mm of precipitation per year.
What is the hottest day ever recorded in Jämsä?
The hottest day measured in Jämsä between 1940 and 2025 was 29 July 2010, reaching 33.4 °C.
What is the coldest day in Jämsä?
The coldest day measured in Jämsä between 1940 and 2025 was 8 January 1987, at -37.5 °C.
Does it snow in Jämsä?
Yes. Jämsä gets on average 135.5 cm of snow per year and has around 160 frost days.
Has the climate of Jämsä warmed?
Yes: Jämsä warmed by +2.4 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Jämsä?
The wettest day measured in Jämsä between 1940 and 2025 was 12 August 1972, with 72 mm of rain in 24 hours.
What was the windiest day in Jämsä?
The windiest day measured in Jämsä between 1940 and 2025 was 23 January 1995, with winds reaching 44.4 km/h.
What is the warmest month in Jämsä?
The warmest month in Jämsä is July (16.9 °C on average); the coldest is January (-7.9 °C).
How much does it rain in Jämsä?
Jämsä receives on average 633 mm of precipitation per year, spread over about 132 rainy days.
Is it sunny in Jämsä?
Jämsä gets on average 6.7 hours of sunshine per day, roughly 2,446 hours per year over 1940-2025.
What is the biggest single-day snowfall in Jämsä?
The heaviest 24-hour snowfall measured in Jämsä between 1940 and 2025 was 25 January 2002, with 19.6 cm.
Are there tropical nights in Jämsä?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Jämsä.
What was the most extreme apparent temperature in Jämsä?
In Jämsä, between 1940 and 2025, the highest apparent temperature reached 34.8 °C on 8 August 2010, and the lowest was -42.6 °C on 8 January 1987.
Compare Jämsä with another city
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Nearby cities
The climate around Jämsä