(The Hill) – Record-breaking late-summer heat is forcing multiple school districts to shut down their buildings early in the academic year.

The National Weather Service said Tuesday a heat wave would “persist in the Mid-Atlantic and Northeast through Thursday and linger all week in Texas and neighboring states.”

More than 61 million people are now living under heat advisories, causing mass disruption in school systems across the country. 

Michigan, Pennsylvania, Massachusetts, Ohio, Wisconsin, Iowa, Indiana, Illinois, New Jersey and Missouri have all had K-12 classes disrupted this week over the heat. 

Three public school systems in Western Massachusetts closed early on Wednesday and canceled classes for Thursday afternoon due to the heat. 

“These temperatures make teaching and learning especially difficult in the majority of our buildings that are not air conditioned. For that reason, Westfield Public Schools staff and students will be dismissed early the next two days,” said Superintendent Stefan Czaporowski. 

In Ohio, five school districts closed on Tuesday as temperatures rose into the 90s, causing thousands of students to miss class for the day.

Milwaukee Public Schools, which has 154 schools, canceled classes late Monday and Tuesday, affecting tens of thousands of students. The district also had closures last month over extreme temperatures.

Some 41 percent of U.S. schools do not have proper heating, cooling and ventilation systems, according to a 2020 report from the Government Accountability Office.

Numerous studies have also shown there is a connection between extreme heat and lower scores for students.