The blistering heat wave that canceled July 4th events and knocked out power last week caused record rates of heat illness in parts of the nation, according to an analysis of federal data by POLITICO’s E&E News.
Three U.S. regions set single-day records for heat-related emergency room visits, according to the analysis of federal Centers for Disease Control and Prevention records dating to 2018. The CDC tracks for 10 regions the percentage of emergency-room visits each day that are due to heat or heat-related illness.
In the five-state mid-Atlantic region, 2.1 percent of all ER visits were heat-related on July 3, CDC records show. That broke the previous record of 1.8 percent, set on June 24, 2025, for the region, which includes Delaware, Maryland, Pennsylvania, Virginia, West Virginia and the District of Columbia.
A region made up of New York and New Jersey also hit a record on July 3, when 1.5 percent of ER visits were heat-related.
