Rome or Zurich: which climate?
Rome (Italy) has a hot-summer mediterranean climate, whereas Zurich (Switzerland) has a temperate oceanic 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 Rome and to Zurich.
Rome is warmer than Zurich by 5.9 °C in annual average: 15.2 °C against 9.3 °C.
Zurich gets more rain than Rome: 1,375 mm per year against 860 mm.
Rome gets 10.0 hours of sunshine per day on average, against 8.6 hours in Zurich.
Zurich has warmed by +2.7 °C between 1940 and 2025, against +2.0 °C in Rome. Zurich is therefore warming faster than Rome. Both trends are statistically significant.
Rome averages 43 hot days (≥ 30 °C) and 17 frost days per year; Zurich averages 4 and 76.
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 | Rome | Zurich | Difference |
|---|---|---|---|
| Mean daily temperature | 15.2 °C | 9.3 °C | -5.9 °C |
| Average daily high | 20.1 °C | 13.1 °C | -7.0 °C |
| Average daily low | 10.7 °C | 5.8 °C | -4.9 °C |
| Annual rainfall | 860 mm | 1,375 mm | +515 mm |
| Sunshine / day | 10.0 h | 8.6 h | -1.4 h |
| Hot days (≥ 30 °C) | 43 d/yr | 4 d/yr | -39 d/yr |
| Frost days (< 0 °C) | 17 d/yr | 76 d/yr | +59 d/yr |
| Rainy days (≥ 1 mm) | 107 d/yr | 171 d/yr | +64 d/yr |
| Mean relative humidity | 74 % | 78 % | +4 % |
| Average peak wind | 13.8 km/h | 9.4 km/h | -4.4 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.