Autumn 2026 officially begins at 11:45 am next Friday (20), but the new season should not bring immediate cold to Brazil. According to Climatempo, the tendency is for the initial period to be marked by muggy weather, rain showers and still high temperatures, with a more significant change only from May onwards.
In recent weeks, some cities in the South and Southeast have recorded a temporary drop in temperatures, which led many people to believe that the cold of autumn had arrived early.
According to experts, this specific cooling was caused by the passage of a more intense than normal for March, which brought a mass of cold air to parts of the South and Southeast. The combination of moist winds, increased cloud cover and frequent rain helped to temporarily reduce temperatures in these regions.
In Curitiba, for example, there was a maximum of 21.1°C, the lowest of the year so far. In São Paulo, the maximum temperature reached 22.3°C, the lowest recorded for a day in March since 2024. Rio de Janeiro also had one of the coolest afternoons of the year, with 24.2°C.
Despite this, meteorologists explain that the phenomenon does not mean that autumn has started early. The atmosphere does not follow the calendar rigidly, and they can occur even during the summer. The expectation is that, with the removal of this mass of cold air, temperatures will rise again in the last week of summer and the beginning of autumn.
According to meteorological projections, characteristics similar to summer, with heat, a feeling of stuffiness and rain showers in several regions of the country. The most noticeable cooling tends to only occur in May, when the gradual reduction in hours of sunlight begins to favor milder temperatures.
The forecast indicates that the first most intense polar air mass of autumn may arrive in Brazil in the transition between May and June. If the scenario is confirmed, the South of the country may experience more severe cold and the possibility of frost, while cities in the Southeast, such as São Paulo, may experience minimum temperatures close to 10°C.
Meteorologists emphasize, however, that long-term forecasts may still change as new atmospheric data is analyzed in the coming weeks. Until then, the beginning of autumn should continue with heat, high humidity and frequent episodes of rain in much of the country.
