Overview
- A stalled upper‑level high-pressure system peaked Thursday, July 2, producing multi-day extreme heat and very warm nights across the central and eastern United States.
- The National Weather Service says more than 160 million people are under major or extreme heat risk as heat-index values hit triple digits in many metro areas.
- Major cities broke or tied daily records on Thursday, and utilities and transport services reported strain including voltage reductions, outages, data‑center backup orders, and reduced Amtrak speeds.
- Cities and federal organizers expanded cooling centers, extended pool hours, added water and medical stations, and altered or shortened July 4 events to protect crowds and vulnerable residents.
- Climate analysis and observations link the event to human-caused warming: Copernicus reported record sea‑surface temperatures on June 21 and World Weather Attribution found the heat would have been highly unlikely without fossil‑fuel driven warming, with El Niño amplifying risks.