Overview
- A strengthening upper‑level heat dome is spreading eastward and is forecast to drive multi‑day extreme heat through the July 4 holiday weekend.
- National Weather Service offices have issued Heat Advisories, Extreme Heat Watches and Warnings that cover tens of millions of people, with public trackers showing more than 74 million currently under alerts.
- Daytime highs are expected in the 90s to low 100s Fahrenheit with heat‑index values as high as about 105–115°F, while many areas face unusually warm overnight lows that limit nighttime recovery.
- Cities and counties have opened cooling centers, cancelled or altered outdoor events and deployed outreach teams to check on vulnerable residents as officials urge hydration and reduced outdoor exertion.
- Forecasters warn the prolonged heat could push energy demand near record levels and disrupt transport and services, with some models suggesting partial relief may arrive late in the weekend but timing and extent remain uncertain.