A severe heat wave is sweeping across the central and eastern United States, bringing dangerous conditions just as Americans prepare for Independence Day celebrations. The National Weather Service has warned of record-breaking temperatures combined with high humidity that will create hazardous heat index values across the region.
Temperatures between 95F and 105F, combined with high humidity, are pushing heat index values to between 100F and 115F across much of the affected area. The National Weather Service stated this will create "widespread areas of major to extreme heat risk from the Midwest to the East Coast," with numerous daily temperature records expected through Friday and Independence Day itself. Some areas may see consecutive-day, monthly, and all-time records broken.
The extreme heat is expected to continue across most of the central and eastern US through Friday, then shift focus to the eastern US through the Independence Day weekend. Peak heat indices could reach as high as 115 degrees in some locations.
The agency emphasized that "prolonged periods of extreme heat are among the deadliest weather hazards" in the country because impacts accumulate over time. Officials urged residents to limit time outdoors, stay hydrated, and ensure access to air conditioning or cooling centers.
In New York City, temperatures reached 100F in Central Park on Thursday afternoon, marking the park's first triple-digit day since July 2012. Forecasters warned of dangerous heat and humidity through Saturday, with heat index values potentially reaching 115F. New York City Mayor Zohran Mamdani urged residents to prepare, stating "Please stay prepared and informed as these dangerously high temperatures continue." He announced that the city was deploying cooling vans staffed with medical personnel who would provide wellness checks, medical care, water, electrolytes, and sunscreen, along with transport to cooling centers.
New York Governor Kathy Hochul warned that the state's electric grid was under heavy strain from increased energy demand. She encouraged residents to voluntarily conserve power by setting air conditioning between 75F and 78F and avoiding unnecessary appliance use.
Across the region, additional impacts emerged. Philadelphia experienced temperatures of 102F on Thursday, and organizers of the city's Independence Day parade shortened the route due to the extreme heat. The mid-Atlantic region faced warnings of heat indices up to 110F, with possible severe thunderstorms adding to dangerous conditions.
Washington DC Mayor Muriel Bowser urged residents to factor the extreme temperatures into their Fourth of July plans, advising people to avoid strenuous outdoor activity, drink plenty of water, wear sunscreen, and limit time outdoors whenever possible.
The dangerous conditions extend across Kentucky, Missouri, Illinois, and Indiana, where heat index values could reach 110F.