Overview
- Extreme heat warnings cover dozens of counties in Arizona, California and Nevada, including Maricopa, Yuma, San Diego and Riverside, through Thursday at 8 p.m.
- Heat advisories now span 20 states from the Northwest to the East Coast, urging millions to limit sun exposure and stay hydrated.
- Temperatures are forecast to reach up to 119°F in the warned regions, with Phoenix expected to peak near 117°F.
- The National Weather Service warns that overexposure can lead to heat cramps, exhaustion and heat stroke, calling extreme heat the deadliest U.S. weather hazard.
- OSHA and CDC guidance recommend frequent breaks in shaded or air-conditioned spaces, regular hydration and immediate medical attention for heat-related emergencies.