Bollnäs climate — normals and trends
Bollnäs (Sweden) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 4.6 °C and it receives 665 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 (16.1 °C on average) and the coldest is January (-5.9 °C). Rainfall peaks in July.
Bollnäs averages 160 frost days, 0 hot days (≥ 30 °C) and 125 rainy days per year.
Bollnäs has warmed by +1.7 °C between 1940 and 2025, or +0.20 °C per decade. This trend is statistically significant.
The number of frost days there went from about 169 to 151 per year over the period.
The hottest day of the period reached 32.7 °C (on 8 August 1975) and the coldest -32.5 °C (on 27 January 1985).
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
BollnäsGävleborg County
- coords
- 61.35°, 16.39°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
4.6°C
Average daily high
8.1°C
Average daily low
0.9°C
Annual rainfall
665mm
Sunshine / day
7.7h
Mean relative humidity
78%
Average peak wind
15.9km/h
Seasonal range
22.0°C
Frost days (< 0 °C)
160 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
125 d/yr
Annual snowfall
143.7 cm
Average feels-like high
4.9 °C
Average feels-like low
-2.6 °C
Average peak gust
36.1 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
9.3 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.7 °C
since 1940
+0.2 °C per decade · r² = 0.22 · 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
32.7 °C
8 August 1975
Coldest day
-32.5 °C
27 January 1985
Wettest day
46 mm
6 September 1985
Windiest day
43.3 km/h
27 December 2025
Strongest gust
97.9 km/h
26 December 2011
Hottest feels-like
33.8 °C
8 August 1975
Coldest feels-like
-37.5 °C
27 January 1985
Snowiest day
20.1 cm
31 October 2006
Sunniest day
18.0 h
25 June 2023
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | -0.3 °C | +3.2 °C | 104 mm | +62 mm |
| Feb | 0.4 °C | +2.8 °C | 10 mm | -22 mm |
| Mar | 6.9 °C | +4.7 °C | 13 mm | -19 mm |
| Apr | 11.3 °C | +3.7 °C | 34 mm | -9 mm |
| May | 13.1 °C | -0.8 °C | 51 mm | +1 mm |
| Jun | 18.2 °C | -0.2 °C | 95 mm | +24 mm |
| Jul | 22.8 °C | +2.4 °C | 123 mm | +33 mm |
| Aug | 19.1 °C | +0.2 °C | 50 mm | -37 mm |
| Sep | 17.0 °C | +2.8 °C | 100 mm | +40 mm |
| Oct | 9.6 °C | +1.6 °C | 71 mm | +16 mm |
| Nov | 3.4 °C | +1.8 °C | 34 mm | -21 mm |
| Dec | 3.3 °C | +4.9 °C | 41 mm | -7 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 Bollnäs?
Bollnäs has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 4.6 °C and it receives 665 mm of precipitation per year.
What is the hottest day ever recorded in Bollnäs?
The hottest day measured in Bollnäs between 1940 and 2025 was 8 August 1975, reaching 32.7 °C.
What is the coldest day in Bollnäs?
The coldest day measured in Bollnäs between 1940 and 2025 was 27 January 1985, at -32.5 °C.
Does it snow in Bollnäs?
Yes. Bollnäs gets on average 143.7 cm of snow per year and has around 160 frost days.
Has the climate of Bollnäs warmed?
Yes: Bollnäs warmed by +1.7 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Bollnäs?
The wettest day measured in Bollnäs between 1940 and 2025 was 6 September 1985, with 46 mm of rain in 24 hours.
What was the windiest day in Bollnäs?
The windiest day measured in Bollnäs between 1940 and 2025 was 27 December 2025, with winds reaching 43.3 km/h.
What is the warmest month in Bollnäs?
The warmest month in Bollnäs is July (16.1 °C on average); the coldest is January (-5.9 °C).
How much does it rain in Bollnäs?
Bollnäs receives on average 665 mm of precipitation per year, spread over about 125 rainy days.
Is it sunny in Bollnäs?
Bollnäs gets on average 7.7 hours of sunshine per day, roughly 2,811 hours per year over 1940-2025.
What is the biggest single-day snowfall in Bollnäs?
The heaviest 24-hour snowfall measured in Bollnäs between 1940 and 2025 was 31 October 2006, with 20.1 cm.
Are there tropical nights in Bollnäs?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Bollnäs.
What was the most extreme apparent temperature in Bollnäs?
In Bollnäs, between 1940 and 2025, the highest apparent temperature reached 33.8 °C on 8 August 1975, and the lowest was -37.5 °C on 27 January 1985.
Compare Bollnäs with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Bollnäs