A powerful heat wave spread across the eastern United States on Wednesday after moving through the Midwest. The dangerous weather placed tens of millions of people under heat warnings. Forecasters said the extreme heat could continue through the July 4 holiday weekend as the country marks its 250th anniversary.
Weather experts warned that many places could see “feels like” temperatures between 100 and 115 degrees Fahrenheit. High humidity will make the air feel even hotter. These conditions raise the risk of heat-related illness, especially for older adults, young children, and people with health problems.
Officials also warned that heavy use of air conditioners could put extra pressure on power systems. Electricity demand continues to grow as more homes, businesses, data centers, and electric vehicles use more power during hot weather.
In Hill City, Kansas, mail carrier Sabrina Hooper faced the extreme heat during only her first week on the job. She walks as much as 10 miles each day while delivering mail and packages.
Hooper said the heat makes the work much harder. She looks for small ways to cool down during her route. Lawn sprinklers provide brief relief, allowing her to wet her hat before continuing her deliveries.
Hill City has seen severe heat before. In 2012, the town recorded some of the nation’s highest temperatures during another major heat wave. The heat index reached 108 degrees, showing how humidity can make the weather feel much hotter than the actual air temperature.
Farther south, families in Texas also struggled with the rising temperatures.
In Brownsville, near the Gulf Coast and the U.S.-Mexico border, Dana Robles worried about the cost of keeping her home cool. During the hottest months, her family’s electricity bill can rise above $300. That amount is close to one-third of what the family pays for rent.
She also expressed concern about possible power outages if the electric grid becomes overloaded. A long blackout during extreme heat could spoil food and make homes unsafe for families.
Residents in Chicago prepared before the hottest weather arrived.
High school science teacher Michelle Klein completed her grocery shopping early. She filled her car with fuel, stocked cold drinks, and watered her plants before temperatures climbed higher.
Even during her evening walk, the heat index reached about 103 degrees. She said some plants needed extra water because of the intense heat.
In the Chicago suburbs, property investor Amy Kaspar received an urgent call from a tenant whose air conditioner seemed to stop working.
After checking the system, she found that the unit was still operating. However, the outdoor heat and high humidity were so intense that the air conditioner could not cool the apartment as quickly as normal.
Local officials urged people to check on family members, neighbors, older adults, and anyone who may need help during the heat. City leaders also reminded residents that well-being checks are available for people who cannot be reached.
The dangerous weather reached New York City on Wednesday. Local officials opened hundreds of cooling centers where people could escape the heat. Special vehicles also traveled through neighborhoods with drinking water, electrolyte drinks, sunscreen, and meals for people in need.
Senior centers across the city stayed cool with full air conditioning. Some locations planned to remain open longer than usual throughout the holiday weekend so more people could stay safe.
New York officials also asked businesses to help reduce electricity use during peak hours. Building operators were encouraged to keep indoor temperatures at moderate levels instead of setting air conditioners too low. Operators of large electronic signs in Times Square were also asked to reduce brightness to lower energy demand.
The city expanded public services by extending swimming pool hours, opening more cooling centers in libraries and public buildings, and increasing outreach teams to assist vulnerable residents.
The heat wave in the United States came as parts of western Europe also experienced record-breaking temperatures. Climate researchers have found that rising global temperatures are increasing both the frequency and strength of heat waves around the world. Studies over many years show that greenhouse gas emissions are making extreme heat events more likely.
Forecasters expect dangerous temperatures to continue across many eastern states through the holiday weekend. Health officials continue to advise people to drink plenty of water, avoid long periods outdoors during the hottest part of the day, wear light clothing, and check on anyone who may be at greater risk from the extreme heat.

