Istanbul or Sydney: which climate?
Istanbul (Republic of Türkiye) has a hot-summer mediterranean climate, whereas Sydney (Australia) 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 Istanbul and to Sydney.
Sydney is warmer than Istanbul by 3.2 °C in annual average: 17.7 °C against 14.5 °C.
Sydney gets more rain than Istanbul: 892 mm per year against 697 mm.
Sydney gets 10.2 hours of sunshine per day on average, against 9.5 hours in Istanbul.
Istanbul has warmed by +1.6 °C between 1940 and 2025, against +1.2 °C in Sydney. Istanbul is therefore warming faster than Sydney. Both trends are statistically significant.
Istanbul averages 3 hot days (≥ 30 °C) and 5 frost days per year; Sydney averages 2 and 0.
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 | Sydney | Difference |
|---|---|---|---|
| Mean daily temperature | 14.5 °C | 17.7 °C | +3.2 °C |
| Average daily high | 16.8 °C | 20.1 °C | +3.3 °C |
| Average daily low | 12.5 °C | 15.5 °C | +3.0 °C |
| Annual rainfall | 697 mm | 892 mm | +195 mm |
| Sunshine / day | 9.5 h | 10.2 h | +0.7 h |
| Hot days (≥ 30 °C) | 3 d/yr | 2 d/yr | negligible |
| Frost days (< 0 °C) | 5 d/yr | 0 d/yr | -5 d/yr |
| Rainy days (≥ 1 mm) | 105 d/yr | 116 d/yr | +11 d/yr |
| Mean relative humidity | 76 % | 72 % | -4 % |
| Average peak wind | 21.4 km/h | 25.9 km/h | +4.5 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.