(Toledo) A wave of heat and humidity in the Midwest and Northeast of the United States, days before the official start of summer, has put a damper on outdoor activities, which it There are festivals or sports camps, and authorities have urged people to take precautions.

Cities that opened cooling centers this week said the Juneteenth holiday will close some public libraries, senior centers and swimming pools where residents might battle the heat.

According to the National Weather Service, dangerous temperatures are 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 heat index is expected to reach 37.7°C to 40.5°C in many places.

In Toledo, Ohio, the city canceled a weekly fitness event and a nearby suburb canceled a street fair as temperatures approached 35°C. A food bank in upstate New York canceled its Wednesday deliveries out of fear for its staff and volunteers.

Schools across New York state canceled field trips to the Rosamond Gifford Zoo in Syracuse, where employees turned on water misters for visitors and animals. Elephants and other animals were getting chunks of ice in their pools, said Ted Fox, the zoo’s executive director.

“Even tigers love to lick the ice and put their heads on it when it’s so hot,” Mr Fox said.

Climate change is causing heat waves to move more slowly and affect more people for longer, according to a recent study. Last year, the United States experienced the most heat waves ― abnormally hot weather that lasts more than two days ― since 1936.

On Monday, Chicago broke a 1957 temperature record with a high of 36.1°C. Wednesday will be another warm day, but a cold front will bring relief to areas near Lake Michigan on Thursday and Friday, according to the National Weather Service in Chicago.

That reprieve won’t come in time for all but one of Chicago’s refreshment centers to close for the Juneteenth holiday.

“It is extremely alarming that we are reducing the number of our cooling centers in the middle of a heat wave,” denounced Lindsey LaPointe, state representative, to the Chicago Sun-Times. Ms. LaPointe represents Chicago’s Northwest Side and advocates on behalf of people without permanent shelter and other vulnerable populations.

Authorities urged people to limit outdoor activities where possible and to check on family members and neighbors who may be vulnerable to the heat.

In New York, Governor Kathy Hochul activated the National Guard to deal with any heat-related emergencies that may arise in the coming days. She also announced that entry 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 are doing our best to ensure all lives are protected,” Hochul said Tuesday.

In California, wildfires broke out east of San Francisco, in the historic Gold Country, and in the mountains of northern Los Angeles County, after a mostly quiet start to the fire season. In southern New Mexico, fires damaged 500 buildings Tuesday in a mountain village of 7,000 residents that had been evacuated shortly before.

Meanwhile, a new wave of tropical moisture posed a growing threat of heavy rain and flash flooding to the central Gulf Coast. This year’s hurricane season is expected to be one of the most active in recent memory.