Red Heat Alert Covers 1,284 Brazilian Cities as Record Temperatures Grip Southeast

Overview

• Inmet kept its maximum red alert in effect through at least Monday for 1,284 municipalities, including all of São Paulo and Rio de Janeiro and parts of Paraná, Minas Gerais and Espírito Santo.
• São Paulo set a new December and 2025 high at 37.2 °C at the Mirante de Santana station, while Piracicaba hit 38.0 °C and Taubaté reached 37.7 °C, with capital anomalies reported near 7–8 °C above normal.
• Meteorologists attribute the persistence to a high‑level cyclonic vortex that established an atmospheric blocking pattern, trapping hot, dry air over the Centre‑South.
• Health risks remain acute, with Rio de Janeiro averaging about 450 daily attendances tied to the heat and authorities urging hydration, cooling measures and water conservation as São Paulo’s metropolitan reservoirs fell to 26.2%.
• Forecasts from Inmet and MetSul point to increasing showers and storms from Dec. 29–31 that should lower temperatures into early January, with hazards including heavy rain, strong winds and hail.