Selfoss climate — normals and trends
Selfoss (Iceland) has a subarctic climate (Dfc) under the Köppen-Geiger classification. Its mean annual temperature is 4.0 °C and it receives 1,523 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 (11.0 °C on average) and the coldest is January (-1.8 °C). Rainfall peaks in October.
Selfoss averages 136 frost days, 0 hot days (≥ 30 °C) and 197 rainy days per year.
Selfoss has warmed by +2.3 °C between 1940 and 2025, or +0.27 °C per decade. This trend is statistically significant.
The number of frost days there went from about 165 to 107 per year over the period.
The hottest day of the period reached 24.3 °C (on 14 July 2025) and the coldest -24.3 °C (on 24 January 1966).
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
SelfossSouth
- coords
- 63.93°, -21.00°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
4.0°C
Average daily high
6.4°C
Average daily low
1.3°C
Annual rainfall
1,523mm
Sunshine / day
6.5h
Mean relative humidity
81%
Average peak wind
18.0km/h
Seasonal range
12.8°C
Frost days (< 0 °C)
136 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
197 d/yr
Annual snowfall
215.6 cm
Average feels-like high
3.0 °C
Average feels-like low
-2.4 °C
Average peak gust
41.7 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
7.8 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.3 °C
since 1940
+0.3 °C per decade · r² = 0.44 · 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
24.3 °C
14 July 2025
Coldest day
-24.3 °C
24 January 1966
Wettest day
68 mm
25 August 1968
Windiest day
77.9 km/h
3 February 1991
Strongest gust
162.7 km/h
16 February 1981
Hottest feels-like
25.7 °C
31 July 1980
Coldest feels-like
-29.5 °C
24 January 1966
Snowiest day
21.5 cm
28 December 2012
Sunniest day
19.6 h
22 June 1940
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 | 0.2 °C | -0.4 °C | 171 mm | +17 mm |
| Feb | 4.8 °C | +3.6 °C | 194 mm | +55 mm |
| Mar | 4.7 °C | +2.2 °C | 202 mm | +64 mm |
| Apr | 7.5 °C | +2.2 °C | 75 mm | -40 mm |
| May | 11.2 °C | +2.0 °C | 94 mm | -6 mm |
| Jun | 10.9 °C | -1.1 °C | 96 mm | +5 mm |
| Jul | 14.3 °C | +0.7 °C | 96 mm | +6 mm |
| Aug | 13.8 °C | +0.8 °C | 109 mm | -2 mm |
| Sep | 11.2 °C | +1.2 °C | 196 mm | +55 mm |
| Oct | 6.2 °C | +0.1 °C | 144 mm | -11 mm |
| Nov | 2.6 °C | -0.2 °C | 55 mm | -85 mm |
| Dec | 4.8 °C | +3.8 °C | 114 mm | -38 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 Selfoss?
Selfoss has a subarctic climate (Köppen Dfc). Over 1940-2025, the average annual temperature is 4.0 °C and it receives 1,523 mm of precipitation per year.
What is the hottest day ever recorded in Selfoss?
The hottest day measured in Selfoss between 1940 and 2025 was 14 July 2025, reaching 24.3 °C.
What is the coldest day in Selfoss?
The coldest day measured in Selfoss between 1940 and 2025 was 24 January 1966, at -24.3 °C.
Does it snow in Selfoss?
Yes. Selfoss gets on average 215.6 cm of snow per year and has around 136 frost days.
Has the climate of Selfoss warmed?
Yes: Selfoss warmed by +2.3 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Selfoss?
The wettest day measured in Selfoss between 1940 and 2025 was 25 August 1968, with 68 mm of rain in 24 hours.
What was the windiest day in Selfoss?
The windiest day measured in Selfoss between 1940 and 2025 was 3 February 1991, with winds reaching 77.9 km/h.
What is the warmest month in Selfoss?
The warmest month in Selfoss is July (11.0 °C on average); the coldest is January (-1.8 °C).
How much does it rain in Selfoss?
Selfoss receives on average 1,523 mm of precipitation per year, spread over about 197 rainy days.
Is it sunny in Selfoss?
Selfoss gets on average 6.5 hours of sunshine per day, roughly 2,373 hours per year over 1940-2025.
What is the biggest single-day snowfall in Selfoss?
The heaviest 24-hour snowfall measured in Selfoss between 1940 and 2025 was 28 December 2012, with 21.5 cm.
Are there tropical nights in Selfoss?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Selfoss.
What was the most extreme apparent temperature in Selfoss?
In Selfoss, between 1940 and 2025, the highest apparent temperature reached 25.7 °C on 31 July 1980, and the lowest was -29.5 °C on 24 January 1966.
Compare Selfoss with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Selfoss