Buenos Aires or Porto: which climate?
Buenos Aires (Argentina) has a humid subtropical climate, whereas Porto (Portugal) has a warm-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 Buenos Aires and to Porto.
Buenos Aires is warmer than Porto by 2.4 °C in annual average: 17.2 °C against 14.8 °C.
Porto gets more rain than Buenos Aires: 1,278 mm per year against 992 mm.
Porto gets 10.0 hours of sunshine per day on average, against 9.6 hours in Buenos Aires.
Porto has warmed by +1.3 °C between 1940 and 2025, against +0.6 °C in Buenos Aires. Porto 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; Porto averages 11 and 1.
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 | Porto | Difference |
|---|---|---|---|
| Mean daily temperature | 17.2 °C | 14.8 °C | -2.4 °C |
| Average daily high | 20.4 °C | 18.5 °C | -1.9 °C |
| Average daily low | 14.2 °C | 11.5 °C | -2.7 °C |
| Annual rainfall | 992 mm | 1,278 mm | +286 mm |
| Sunshine / day | 9.6 h | 10.0 h | +0.4 h |
| Hot days (≥ 30 °C) | 11 d/yr | 11 d/yr | negligible |
| Frost days (< 0 °C) | 0 d/yr | 1 d/yr | negligible |
| Rainy days (≥ 1 mm) | 93 d/yr | 120 d/yr | +27 d/yr |
| Mean relative humidity | 75 % | 79 % | +4 % |
| Average peak wind | 22.6 km/h | 17.4 km/h | -5.2 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.