Brazil Swelters in Sixth 2025 Heat Wave as South Braces for Cyclone-Driven Storms

Overview

• Temperatures above 40°C persist through Monday across interior areas, with Inmet and state Defesa Civil warning of very low humidity near 12% to 25% and elevated wildfire and health risks.
• Rio Grande do Sul faces the weekend’s most severe weather as a forming oceanic cyclone brings heavy rain, hail potential and wind gusts that may top 100 km/h, with hydrological alerts in place.
• In the North, Inmet alerts call for heavy downpours up to roughly 50 mm/day and winds near 60 km/h in parts of Amazonas, Acre, Rondônia, Roraima, Mato Grosso and Pará.
• Heat returns to São Paulo this weekend with highs near 33°C before a front late Sunday ushers in a sharp drop and the risk of strong winds, storms and isolated hail, with cooler conditions expected next week.
• Spring begins Monday at 15:19 local time, and Climatempo notes a likely shift to cooler episodes in the coming weeks, with La Niña forecast to develop in October and increase temperature swings.