Hamburg or Istanbul: which climate?
Hamburg (Germany) has a temperate oceanic climate, whereas Istanbul (Republic of Türkiye) 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 Hamburg and to Istanbul.
Istanbul is warmer than Hamburg by 5.5 °C in annual average: 14.5 °C against 9.0 °C.
Hamburg and Istanbul receive comparable annual rainfall, on the order of 733 mm.
Istanbul gets 9.5 hours of sunshine per day on average, against 7.2 hours in Hamburg.
Hamburg has warmed by +2.2 °C between 1940 and 2025, against +1.6 °C in Istanbul. Hamburg is therefore warming faster than Istanbul. Both trends are statistically significant.
Hamburg averages 3 hot days (≥ 30 °C) and 67 frost days per year; Istanbul averages 3 and 5.
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 | Hamburg | Istanbul | Difference |
|---|---|---|---|
| Mean daily temperature | 9.0 °C | 14.5 °C | +5.5 °C |
| Average daily high | 12.4 °C | 16.8 °C | +4.4 °C |
| Average daily low | 5.8 °C | 12.5 °C | +6.7 °C |
| Annual rainfall | 733 mm | 697 mm | negligible |
| Sunshine / day | 7.2 h | 9.5 h | +2.3 h |
| Hot days (≥ 30 °C) | 3 d/yr | 3 d/yr | negligible |
| Frost days (< 0 °C) | 67 d/yr | 5 d/yr | -62 d/yr |
| Rainy days (≥ 1 mm) | 144 d/yr | 105 d/yr | -39 d/yr |
| Mean relative humidity | 80 % | 76 % | -4 % |
| Average peak wind | 18.6 km/h | 21.4 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.