Heat Wave Grips Brazil’s Southeast as São Paulo Sets December Record and Rio Hits 40°C

Overview

• São Paulo reached 35.9°C at the Mirante de Santana station on December 25, the highest temperature ever recorded in the city for December and the hottest day of 2025 there.
• Rio de Janeiro hit 40.1°C at the Guaratiba station on December 25 and remains at Calor 3 under the municipal heat protocol, with very hot conditions forecast through the weekend.
• Inmet’s orange heat-wave alert covers all of the Southeast plus parts of Paraná, Santa Catarina, Goiás and Mato Grosso do Sul, and remains valid until 18:00 Friday.
• Health services in Rio reported nearly 1,000 heat-related attendances over two days as the state health secretariat warned 92 municipalities and urged public hydration points.
• Inland São Paulo cities also saw extreme heat, including Sorocaba at 35.7°C and Jundiaí at 35.2°C, as a persistent blocking pattern intensifies a warm, dry air mass across the region.