Athens or Sydney: which climate?
Athens (Greece) 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 Athens and to Sydney.
Athens and Sydney have the same mean annual temperature, about 17.5 °C: the gap between the two cities is too small to be told apart from the noise in the data.
Sydney gets more rain than Athens: 892 mm per year against 364 mm.
Athens has warmed by +1.6 °C between 1940 and 2025, against +1.2 °C in Sydney. Athens is therefore warming faster than Sydney. Both trends are statistically significant.
Athens averages 85 hot days (≥ 30 °C) and 3 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 | Athens | Sydney | Difference |
|---|---|---|---|
| Mean daily temperature | 17.5 °C | 17.7 °C | negligible |
| Average daily high | 22.1 °C | 20.1 °C | -2.0 °C |
| Average daily low | 13.2 °C | 15.5 °C | +2.3 °C |
| Annual rainfall | 364 mm | 892 mm | +528 mm |
| Sunshine / day | 10.4 h | 10.2 h | negligible |
| Hot days (≥ 30 °C) | 85 d/yr | 2 d/yr | -83 d/yr |
| Frost days (< 0 °C) | 3 d/yr | 0 d/yr | negligible |
| Rainy days (≥ 1 mm) | 59 d/yr | 116 d/yr | +57 d/yr |
| Mean relative humidity | 64 % | 72 % | +8 % |
| Average peak wind | 15.4 km/h | 25.9 km/h | +10.5 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.