Olsztyn climate — normals and trends
Olsztyn (Poland) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 7.4 °C and it receives 657 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 (17.7 °C on average) and the coldest is January (-3.3 °C). Rainfall peaks in July.
Olsztyn averages 109 frost days, 2 hot days (≥ 30 °C) and 136 rainy days per year.
Olsztyn has warmed by +2.5 °C between 1940 and 2025, or +0.29 °C per decade. This trend is statistically significant.
The number of frost days there went from about 129 to 89 per year over the period.
The hottest day of the period reached 35.8 °C (on 8 August 2015) and the coldest -32.0 °C (on 31 January 1956).
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
OlsztynWarmia-Masuria
- coords
- 53.78°, 20.49°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
7.4°C
Average daily high
10.7°C
Average daily low
4.0°C
Annual rainfall
657mm
Sunshine / day
7.2h
Mean relative humidity
81%
Average peak wind
19.2km/h
Seasonal range
21.0°C
Frost days (< 0 °C)
109 d/yr
Hot days (≥ 30 °C)
2 d/yr
Rainy days (≥ 1 mm)
136 d/yr
Annual snowfall
71.0 cm
Average feels-like high
7.8 °C
Average feels-like low
0.6 °C
Average peak gust
37.3 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
10.1 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.5 °C
since 1940
+0.3 °C per decade · r² = 0.42 · 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
35.8 °C
8 August 2015
Coldest day
-32.0 °C
31 January 1956
Wettest day
64 mm
3 September 1995
Windiest day
57.6 km/h
17 January 1955
Strongest gust
114.8 km/h
2 November 1981
Hottest feels-like
35.9 °C
11 July 1959
Coldest feels-like
-37.7 °C
31 January 1956
Snowiest day
17.0 cm
30 January 1979
Sunniest day
16.3 h
20 June 2025
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 | 3.6 °C | +4.9 °C | 55 mm | +13 mm |
| Feb | 1.3 °C | +1.4 °C | 17 mm | -21 mm |
| Mar | 10.2 °C | +5.8 °C | 28 mm | -11 mm |
| Apr | 15.0 °C | +3.9 °C | 20 mm | -25 mm |
| May | 14.7 °C | -2.1 °C | 70 mm | +7 mm |
| Jun | 20.8 °C | +0.6 °C | 65 mm | -7 mm |
| Jul | 22.6 °C | +0.8 °C | 123 mm | +35 mm |
| Aug | 21.7 °C | +0.1 °C | 72 mm | +2 mm |
| Sep | 19.2 °C | +2.1 °C | 90 mm | +34 mm |
| Oct | 11.1 °C | -0.1 °C | 68 mm | +21 mm |
| Nov | 5.1 °C | +0.4 °C | 56 mm | +9 mm |
| Dec | 3.9 °C | +3.0 °C | 26 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 Olsztyn?
Olsztyn has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 7.4 °C and it receives 657 mm of precipitation per year.
What is the hottest day ever recorded in Olsztyn?
The hottest day measured in Olsztyn between 1940 and 2025 was 8 August 2015, reaching 35.8 °C.
What is the coldest day in Olsztyn?
The coldest day measured in Olsztyn between 1940 and 2025 was 31 January 1956, at -32.0 °C.
Does it snow in Olsztyn?
Yes. Olsztyn gets on average 71.0 cm of snow per year and has around 109 frost days.
Has the climate of Olsztyn warmed?
Yes: Olsztyn warmed by +2.5 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Olsztyn?
The wettest day measured in Olsztyn between 1940 and 2025 was 3 September 1995, with 64 mm of rain in 24 hours.
What was the windiest day in Olsztyn?
The windiest day measured in Olsztyn between 1940 and 2025 was 17 January 1955, with winds reaching 57.6 km/h.
What is the warmest month in Olsztyn?
The warmest month in Olsztyn is July (17.7 °C on average); the coldest is January (-3.3 °C).
How much does it rain in Olsztyn?
Olsztyn receives on average 657 mm of precipitation per year, spread over about 136 rainy days.
Is it sunny in Olsztyn?
Olsztyn gets on average 7.2 hours of sunshine per day, roughly 2,628 hours per year over 1940-2025.
What is the biggest single-day snowfall in Olsztyn?
The heaviest 24-hour snowfall measured in Olsztyn between 1940 and 2025 was 30 January 1979, with 17.0 cm.
Are there tropical nights in Olsztyn?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Olsztyn.
What was the most extreme apparent temperature in Olsztyn?
In Olsztyn, between 1940 and 2025, the highest apparent temperature reached 35.9 °C on 11 July 1959, and the lowest was -37.7 °C on 31 January 1956.
Compare Olsztyn with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Olsztyn