Buenos Aires or Sydney: which climate?
Buenos Aires (Argentina) has a humid subtropical 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 Buenos Aires and to Sydney.
Sydney is warmer than Buenos Aires by 0.5 °C in annual average: 17.7 °C against 17.2 °C.
Buenos Aires gets more rain than Sydney: 992 mm per year against 892 mm.
Sydney gets 10.2 hours of sunshine per day on average, against 9.6 hours in Buenos Aires.
Sydney has warmed by +1.2 °C between 1940 and 2025, against +0.6 °C in Buenos Aires. Sydney is therefore warming faster than Buenos Aires. Both trends are statistically significant.
Buenos Aires averages 11 hot days (≥ 30 °C) and 0 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 | Buenos Aires | Sydney | Difference |
|---|---|---|---|
| Mean daily temperature | 17.2 °C | 17.7 °C | +0.5 °C |
| Average daily high | 20.4 °C | 20.1 °C | negligible |
| Average daily low | 14.2 °C | 15.5 °C | +1.3 °C |
| Annual rainfall | 992 mm | 892 mm | -100 mm |
| Sunshine / day | 9.6 h | 10.2 h | +0.6 h |
| Hot days (≥ 30 °C) | 11 d/yr | 2 d/yr | -9 d/yr |
| Frost days (< 0 °C) | 0 d/yr | 0 d/yr | negligible |
| Rainy days (≥ 1 mm) | 93 d/yr | 116 d/yr | +23 d/yr |
| Mean relative humidity | 75 % | 72 % | -3 % |
| Average peak wind | 22.6 km/h | 25.9 km/h | +3.3 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.