Buenos Aires or Lyon: which climate?
Buenos Aires (Argentina) has a humid subtropical climate, whereas Lyon (France) 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 Lyon.
Buenos Aires is warmer than Lyon by 5.9 °C in annual average: 17.2 °C against 11.3 °C.
Buenos Aires and Lyon receive comparable annual rainfall, on the order of 992 mm.
Buenos Aires gets 9.6 hours of sunshine per day on average, against 8.8 hours in Lyon.
Lyon has warmed by +2.5 °C between 1940 and 2025, against +0.6 °C in Buenos Aires. Lyon 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; Lyon averages 14 and 54.
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 | Lyon | Difference |
|---|---|---|---|
| Mean daily temperature | 17.2 °C | 11.3 °C | -5.9 °C |
| Average daily high | 20.4 °C | 15.6 °C | -4.8 °C |
| Average daily low | 14.2 °C | 7.3 °C | -6.9 °C |
| Annual rainfall | 992 mm | 961 mm | negligible |
| Sunshine / day | 9.6 h | 8.8 h | -0.8 h |
| Hot days (≥ 30 °C) | 11 d/yr | 14 d/yr | negligible |
| Frost days (< 0 °C) | 0 d/yr | 54 d/yr | +54 d/yr |
| Rainy days (≥ 1 mm) | 93 d/yr | 141 d/yr | +48 d/yr |
| Mean relative humidity | 75 % | 75 % | negligible |
| Average peak wind | 22.6 km/h | 14.9 km/h | -7.7 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.