The city of São Paulo reached 35.9°C on Thursday (December 25), marking the hottest day of 2025 and the hottest December day since 1943. The record was recorded at 4 p.m. at Mirante de Santana by Inmet. The heat is expected to persist in the coming days, with possible rains over the weekend.
São Paulo's capital broke two climate records on this Christmas Thursday. At 3 p.m., thermometers at Mirante de Santana in the north zone marked 35.7°C, rising to 35.9°C at 4 p.m., according to the National Institute of Meteorology (Inmet). This was the highest temperature of the year so far, surpassing the 35.1°C from October 6. Moreover, it is the December record since the historical series began in 1943, when the previous peak was 35.6°C on December 3, 1998.
The heat is driven by a mass of hot and humid air over Brazil's Southeast, ensuring sunny days with above-average temperatures. Inmet issued an orange alert for eight states, including São Paulo, valid until 6 p.m. Friday (December 26), indicating risks of dangerous weather events.
For the coming days, Inmet forecasts highs of 35°C on Friday, 33°C on Saturday (December 27), and 34°C on Sunday (December 28). There is a chance of up to 37°C on Monday (December 29), which could match one of the city's hottest days ever, behind only the 37.8°C from October 2014. The Municipal Center for Climate Emergencies Management (CGE) warns of rains from Friday to Sunday, possibly heavy, with risks of flooding and wind gusts. The muggy weather should continue until Tuesday (December 30), but New Year's Eve promises a cloudy sky, pleasant temperatures, and no precipitation on Wednesday (December 31).
"What favors this heat wave is the action of a pressure system at mid-levels, which acts as an atmospheric block and enhances temperature rises," explains meteorologist Guilherme Borges from the startup FieldPro.
