The summer of 2024/2025, which ended at 6:02 a.m. on Thursday, March 20, went down in history as the sixth hottest in Brazil since 1961. According to the National Institute of Meteorology (Instituto Nacional de Meteorologia /INMET), the temperature was 0.34°C above the average for the period between 1991 and 2020.

Thermometers recorded above-average temperatures in most of the country, with Rio Grande do Sul standing out as it faced three intense heat waves: from January 17 to 23, February 2 to 12, and March 1 to 8, 2025.

Even under the influence of the 'La Niña' phenomenon, which typically lowers the global average temperature, the heat was intense and consolidated this summer among the ten hottest ever recorded. INMET data show that, since the 1990s, Brazilian summers have been progressively getting hotter.

The increase in temperatures is in line with a global trend. In the years 2023/2024, 2015/2016, 1997/1998, and 2009/2010, for example, the world was impacted by "El Niño", a phenomenon characterized by above-average warming of the waters in the Equatorial Pacific Ocean, which intensifies high temperatures in various regions of the planet.

The World Meteorological Organization (WMO) has warned that the last decade was the hottest ever recorded due to the increase in greenhouse gas emissions and global warming.

RAINS — In addition to the extreme heat, the summer of 2024/2025 was marked by significant amounts of rain in some Brazilian regions. States in the North, as well as Maranhão and northern Piauí, recorded accumulations exceeding 700 mm, surpassing the historical average.

Frequent rainfalls in the northern part of the country were driven by the Intertropical Convergence Zone (ITCZ), a weather system formed by the interaction of trade winds from the Northeast, originating in the Northern Hemisphere, also southeast winds from the Southern Hemisphere.

Except for Roraima, rainfall exceeded 500 mm in the Central-North of Brazil, the central-eastern part of the Northeast, the central-southern area of Mato Grosso do Sul, the west of São Paulo, northern Minas Gerais, Espírito Santo, Rio de Janeiro, and the central and western parts of the South Region, where lower volumes were observed.

CENTRAL-WEST AND SOUTHEAST — In the Central-West and Southeast, rains were below average, with values exceeding 600 mm in the central north of Mato Grosso and specific areas of Goiás and São Paulo. During the season, there were three episodes of the South Atlantic Convergence Zone (SACZ), one of the main weather systems contributing to prolonged rains in this region: between December 27 and 31, 2024, between January 6 and 15, 2025, and between January 31 and February 5, 2025.

SOUTH — In the South Region, the passage of frontal systems and areas of instability resulted in rainfall volumes exceeding 500 mm in the east of Paraná and Santa Catarina. However, in the west of Rio Grande do Sul, rainfall was well below average, with accumulations lower than 250 mm, while the historical average for this area ranges between 400 and 500 mm.