Oslo or Warsaw: which climate?
Oslo (Norway) has a warm-summer humid continental climate, whereas Warsaw (Poland) has a warm-summer humid continental climate, according to the Köppen-Geiger classification.
The values compared here are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme. The same method and the same period apply to Oslo and to Warsaw.
Warsaw is warmer than Oslo by 3.4 °C in annual average: 8.4 °C against 5.0 °C.
Oslo gets more rain than Warsaw: 940 mm per year against 638 mm.
Oslo has warmed by +2.8 °C between 1940 and 2025, against +2.4 °C in Warsaw. Oslo is therefore warming faster than Warsaw. Both trends are statistically significant.
Oslo averages 0 hot days (≥ 30 °C) and 148 frost days per year; Warsaw averages 5 and 99.
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
| Indicator | Oslo | Warsaw | Difference |
|---|---|---|---|
| Mean daily temperature | 5.0 °C | 8.4 °C | +3.4 °C |
| Average daily high | 8.3 °C | 12.0 °C | +3.7 °C |
| Average daily low | 1.5 °C | 4.7 °C | +3.2 °C |
| Annual rainfall | 940 mm | 638 mm | -302 mm |
| Sunshine / day | 7.5 h | 7.2 h | negligible |
| Hot days (≥ 30 °C) | 0 d/yr | 5 d/yr | +5 d/yr |
| Frost days (< 0 °C) | 148 d/yr | 99 d/yr | -49 d/yr |
| Rainy days (≥ 1 mm) | 133 d/yr | 131 d/yr | negligible |
| Mean relative humidity | 79 % | 78 % | negligible |
| Average peak wind | 13.7 km/h | 17.4 km/h | +3.7 km/h |
A difference is only reported when it exceeds the resolution of the data. ERA5 is a reanalysis on a grid of about 31 km: two nearby cities often fall in the same cell, and below half a degree you are reading the grid, not the climate.