New York or Rome: which climate?
New York (United States) has a hot-summer humid continental climate, whereas Rome (Italy) has a hot-summer mediterranean 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 New York and to Rome.
Rome is warmer than New York by 3.1 °C in annual average: 15.2 °C against 12.1 °C.
New York gets more rain than Rome: 1,098 mm per year against 860 mm.
Rome gets 10.0 hours of sunshine per day on average, against 8.8 hours in New York.
New York and Rome are warming at the same rate: about +1.7 °C between 1940 and 2025 on both sides.
New York averages 20 hot days (≥ 30 °C) and 75 frost days per year; Rome averages 43 and 17.
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 | New York | Rome | Difference |
|---|---|---|---|
| Mean daily temperature | 12.1 °C | 15.2 °C | +3.1 °C |
| Average daily high | 15.7 °C | 20.1 °C | +4.4 °C |
| Average daily low | 8.6 °C | 10.7 °C | +2.1 °C |
| Annual rainfall | 1,098 mm | 860 mm | -238 mm |
| Sunshine / day | 8.8 h | 10.0 h | +1.2 h |
| Hot days (≥ 30 °C) | 20 d/yr | 43 d/yr | +23 d/yr |
| Frost days (< 0 °C) | 75 d/yr | 17 d/yr | -58 d/yr |
| Rainy days (≥ 1 mm) | 118 d/yr | 107 d/yr | -11 d/yr |
| Mean relative humidity | 71 % | 74 % | +3 % |
| Average peak wind | 17.4 km/h | 13.8 km/h | -3.6 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.