Istanbul or Rome: which climate?
Istanbul (Republic of Türkiye) has a hot-summer mediterranean 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 Istanbul and to Rome.
Rome is warmer than Istanbul by 0.7 °C in annual average: 15.2 °C against 14.5 °C.
Rome gets more rain than Istanbul: 860 mm per year against 697 mm.
Rome gets 10.0 hours of sunshine per day on average, against 9.5 hours in Istanbul.
Rome has warmed by +2.0 °C between 1940 and 2025, against +1.6 °C in Istanbul. Rome is therefore warming faster than Istanbul. Both trends are statistically significant.
Istanbul averages 3 hot days (≥ 30 °C) and 5 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 | Istanbul | Rome | Difference |
|---|---|---|---|
| Mean daily temperature | 14.5 °C | 15.2 °C | +0.7 °C |
| Average daily high | 16.8 °C | 20.1 °C | +3.3 °C |
| Average daily low | 12.5 °C | 10.7 °C | -1.8 °C |
| Annual rainfall | 697 mm | 860 mm | +163 mm |
| Sunshine / day | 9.5 h | 10.0 h | +0.5 h |
| Hot days (≥ 30 °C) | 3 d/yr | 43 d/yr | +40 d/yr |
| Frost days (< 0 °C) | 5 d/yr | 17 d/yr | +12 d/yr |
| Rainy days (≥ 1 mm) | 105 d/yr | 107 d/yr | negligible |
| Mean relative humidity | 76 % | 74 % | negligible |
| Average peak wind | 21.4 km/h | 13.8 km/h | -7.6 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.