Overview
- The worst heat is expected Thursday and Friday with heat-index values commonly 100–115°F, making those days the peak of the multi-day event.
- More than 160 million people are under NWS major or extreme heat risk categories, with local Extreme Heat Warnings and advisories in effect through Friday or Saturday evening in many areas.
- Officials warn high daytime heat and unusually warm nights will raise the risk of heat-related illness for children, older adults, outdoor workers and people without reliable air conditioning.
- Cities, event organizers and grid operators have opened cooling centers, hydration stations, added medical staffing and taken power precautions ahead of large July 4 gatherings.
- Storm chances rise over the holiday weekend with isolated to scattered thunderstorms that could bring damaging winds, hail or heavy rain, and partial relief is likely beginning Sunday as drier air moves in.