Istanbul or Marseille: which climate?
Istanbul (Republic of Türkiye) has a hot-summer mediterranean climate, whereas Marseille (France) 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 Marseille.
Istanbul and Marseille have the same mean annual temperature, about 14.5 °C: the gap between the two cities is too small to be told apart from the noise in the data.
Istanbul and Marseille receive comparable annual rainfall, on the order of 697 mm.
Marseille gets 10.4 hours of sunshine per day on average, against 9.5 hours in Istanbul.
Istanbul and Marseille are warming at the same rate: about +1.6 °C between 1940 and 2025 on both sides.
Istanbul averages 3 hot days (≥ 30 °C) and 5 frost days per year; Marseille averages 1 and 3.
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 | Marseille | Difference |
|---|---|---|---|
| Mean daily temperature | 14.5 °C | 14.8 °C | negligible |
| Average daily high | 16.8 °C | 17.3 °C | +0.5 °C |
| Average daily low | 12.5 °C | 12.5 °C | negligible |
| Annual rainfall | 697 mm | 657 mm | negligible |
| Sunshine / day | 9.5 h | 10.4 h | +0.9 h |
| Hot days (≥ 30 °C) | 3 d/yr | 1 d/yr | negligible |
| Frost days (< 0 °C) | 5 d/yr | 3 d/yr | negligible |
| Rainy days (≥ 1 mm) | 105 d/yr | 78 d/yr | -27 d/yr |
| Mean relative humidity | 76 % | 74 % | negligible |
| Average peak wind | 21.4 km/h | 25.5 km/h | +4.1 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.