Early Blast of Heat and Humidity Leaves Millions Sweltering Across the U.S.

TOLEDO, Ohio (AP) — A blast of heat and humidity in the Midwest and Northeast days before the official start of summer put a wet blanket on outdoor activities from festivals to sports camps as officials urged people to take precautions.

Cities that opened cooling centers this week advised that Wednesday’s Juneteenth holiday means some public libraries, senior centers, and pools where residents could beat the heat will be closed.

The dangerous temperatures were expected to peak in the eastern Great Lakes and New England on Wednesday and Thursday, and in the Ohio Valley and Mid-Atlantic on Friday and Saturday, the National Weather Service said. Heat index readings were expected to reach 100 to 105 degrees (37.7 C to 40.5 C) in many locations.

A recent study found that climate change is making heat waves move more slowly and affect more people for a longer time. Last year, the U.S. saw the most heat waves — abnormally hot weather lasting more than two days — since 1936.

Chicago broke a 1957 temperature record Monday with a high of 97 degrees (36.1 C). Wednesday will be another hot day, but a cold front will bring relief to areas near Lake Michigan on Thursday and Friday, the National Weather Service in Chicago said.

Officials have urged people to limit outdoor activities when possible and to check in with family members and neighbors who may be vulnerable to the heat.

In New York, Gov. Kathy Hochul activated the National Guard to assist in any heat emergencies that develop over the next several days. She also said admission and parking fees at state parks, pools, and beaches would be waived on Wednesday and Thursday.

“This is a time of significant risk, and we’re doing our best to make sure that all lives are protected,” Hochul said Tuesday.

Meanwhile, a fresh batch of tropical moisture was bringing an increasing threat of heavy rain and flash flooding to the central Gulf Coast. Hurricane season this year is forecast to be among the most active in recent memory.