The summer of 2025 was marked by extreme weather events by Brazil. The station started with bulky rain, followed by successive heat waves and prolonged periods of drought. The behavior of rainfall and temperatures had as a determining factor the La Niña phenomenon, according to Climatempo.
The performance of two South Atlantic Convergence Zones (ZCAS) brought heavy rainfall to the Midwest, Southeast and part of the Northeast in December, beginning of the season.
In January, ZCAS was losing strength and atmospheric blocks prevented the arrival of cold fronts in the interior of the country, as a result the region had little precipitation. Already in the north and coast of the Northeast the rains were strong.
The first heat wave took place between January 14 and 19. The heat began to intensify, especially in the south center.
February was the hottest summer, with successive heat waves in south center. As a consequence of the heat, the states of Mato Grosso, Goiás, Minas Gerais, Bahia and much of the Northeast had a strong water deficit.
While some regions suffered from drought, others faced torrential rainfall due to the Intertropical Convergence Zone (ZCIT), which affected Northern Brazil and the Northeast Coast. States such as Maranhão, Piauí and Ceará registered accumulated more than 300 mm of rain.
In March, the North and the Northeast Coast continued to receive heavy rainfall due to ZCIT. Already in the states of São Paulo, Minas Gerais and Paraná, the level of rainfall was reduced. The Midwest kept the drought trend, especially in Mato Grosso and Goiás.
Extreme rainfall
In Sao Paulo, on January 24, more than 140 mm of rain were recorded in just 3 hours. The day has become a chaos with flooding, overflowing rivers and streams, urban mobility problems, among others.
The large accumulated within hours also occurred in Curitiba, with more than 80 mm of accumulated in 4 hours. In Greater Florianópolis, the accumulated rainfall exceeded 350 mm between January 15 and 17.
Heat waves
The five heat waves recorded along the season made it difficult to form rain clouds in the south center. As a result the region has undergone prolonged drought periods and record temperatures.
La Niña’s performance intensified drought in southern Brazil and favored below average rainfall in Rio Grande do Sul and part of Santa Catarina.
