London or Vienna: which climate?
London (United Kingdom) has a temperate oceanic climate, whereas Vienna (Austria) 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 London and to Vienna.
London and Vienna have the same mean annual temperature, about 10.2 °C: the gap between the two cities is too small to be told apart from the noise in the data.
London and Vienna receive comparable annual rainfall, on the order of 615 mm.
Vienna gets 8.3 hours of sunshine per day on average, against 7.5 hours in London.
Vienna has warmed by +2.4 °C between 1940 and 2025, against +1.8 °C in London. Vienna is therefore warming faster than London. Both trends are statistically significant.
London averages 1 hot days (≥ 30 °C) and 36 frost days per year; Vienna averages 12 and 83.
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 | London | Vienna | Difference |
|---|---|---|---|
| Mean daily temperature | 10.2 °C | 9.9 °C | negligible |
| Average daily high | 13.4 °C | 14.0 °C | +0.6 °C |
| Average daily low | 6.9 °C | 6.1 °C | -0.8 °C |
| Annual rainfall | 615 mm | 639 mm | negligible |
| Sunshine / day | 7.5 h | 8.3 h | +0.8 h |
| Hot days (≥ 30 °C) | 1 d/yr | 12 d/yr | +11 d/yr |
| Frost days (< 0 °C) | 36 d/yr | 83 d/yr | +47 d/yr |
| Rainy days (≥ 1 mm) | 123 d/yr | 118 d/yr | -5 d/yr |
| Mean relative humidity | 80 % | 74 % | -6 % |
| Average peak wind | 20.4 km/h | 18.3 km/h | negligible |
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.