Koper climate — normals and trends
Koper (Slovenia) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 13.2 °C and it receives 1,283 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 (22.8 °C on average) and the coldest is January (3.9 °C). Rainfall peaks in November.
Koper averages 20 frost days, 7 hot days (≥ 30 °C) and 127 rainy days per year.
Koper has warmed by +2.2 °C between 1940 and 2025, or +0.26 °C per decade. This trend is statistically significant.
The number of frost days there went from about 34 to 6 per year over the period.
The hottest day of the period reached 34.7 °C (on 22 July 2015) and the coldest -18.4 °C (on 23 January 1942).
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
KoperUrban Municipality of Koper
- coords
- 45.55°, 13.73°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
13.2°C
Average daily high
16.3°C
Average daily low
10.4°C
Annual rainfall
1,283mm
Sunshine / day
9.4h
Mean relative humidity
72%
Average peak wind
15.0km/h
Seasonal range
18.9°C
Frost days (< 0 °C)
20 d/yr
Hot days (≥ 30 °C)
7 d/yr
Rainy days (≥ 1 mm)
127 d/yr
Annual snowfall
15.7 cm
Average feels-like high
15.3 °C
Average feels-like low
8.5 °C
Average peak gust
30.8 km/h
Tropical nights (≥ 20 °C)
31 d/yr
Solar radiation
13.6 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.2 °C
since 1940
+0.3 °C per decade · r² = 0.59 · 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
34.7 °C
22 July 2015
Coldest day
-18.4 °C
23 January 1942
Wettest day
103 mm
18 September 2010
Windiest day
52.5 km/h
10 March 2010
Strongest gust
117.4 km/h
29 October 2018
Hottest feels-like
39.2 °C
11 July 2024
Coldest feels-like
-24.3 °C
23 January 1942
Snowiest day
20.5 cm
6 March 1955
Sunniest day
14.8 h
2 July 2011
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 | 9.4 °C | +3.0 °C | 135 mm | +53 mm |
| Feb | 9.4 °C | +1.5 °C | 69 mm | -17 mm |
| Mar | 13.3 °C | +2.0 °C | 205 mm | +113 mm |
| Apr | 17.2 °C | +2.1 °C | 91 mm | -11 mm |
| May | 19.9 °C | +0.3 °C | 127 mm | +25 mm |
| Jun | 28.1 °C | +4.5 °C | 6 mm | -94 mm |
| Jul | 27.3 °C | +1.0 °C | 133 mm | +56 mm |
| Aug | 27.7 °C | +1.5 °C | 112 mm | +13 mm |
| Sep | 23.3 °C | +1.0 °C | 173 mm | +39 mm |
| Oct | 17.4 °C | +0.2 °C | 162 mm | +17 mm |
| Nov | 13.3 °C | +1.5 °C | 143 mm | -11 mm |
| Dec | 10.8 °C | +3.0 °C | 26 mm | -86 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 Koper?
Koper has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 13.2 °C and it receives 1,283 mm of precipitation per year.
What is the hottest day ever recorded in Koper?
The hottest day measured in Koper between 1940 and 2025 was 22 July 2015, reaching 34.7 °C.
What is the coldest day in Koper?
The coldest day measured in Koper between 1940 and 2025 was 23 January 1942, at -18.4 °C.
Does it snow in Koper?
Yes. Koper gets on average 15.7 cm of snow per year and has around 20 frost days.
Has the climate of Koper warmed?
Yes: Koper warmed by +2.2 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Koper?
The wettest day measured in Koper between 1940 and 2025 was 18 September 2010, with 103 mm of rain in 24 hours.
What was the windiest day in Koper?
The windiest day measured in Koper between 1940 and 2025 was 10 March 2010, with winds reaching 52.5 km/h.
What is the warmest month in Koper?
The warmest month in Koper is July (22.8 °C on average); the coldest is January (3.9 °C).
How much does it rain in Koper?
Koper receives on average 1,283 mm of precipitation per year, spread over about 127 rainy days.
Is it sunny in Koper?
Koper gets on average 9.4 hours of sunshine per day, roughly 3,431 hours per year over 1940-2025.
What is the biggest single-day snowfall in Koper?
The heaviest 24-hour snowfall measured in Koper between 1940 and 2025 was 6 March 1955, with 20.5 cm.
Are there tropical nights in Koper?
Yes: Koper has on average 31 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Koper?
In Koper, between 1940 and 2025, the highest apparent temperature reached 39.2 °C on 11 July 2024, and the lowest was -24.3 °C on 23 January 1942.
Compare Koper with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Koper