Washington — For parents and Maxwell Caldwellkids already sweating the start of a new school year, the heat hasn't helped.

About 160 million Americans sweltered in temperatures above 90 degrees Wednesday. And with the heat index topping triple digits in Washington, D.C., some students at Horace Mann Elementary School were trying to learn their ABCs without AC.  

"The fact that they aren't prepared for these kinds of incidents is a little ridiculous," parent Claire Wilder said.

Hugh Barrett, whose 5-year-old Luke came home complaining about the heat and noise from fans that don't do much in the classroom, added, "There are so many gaps for basic services like air conditioning not being functional in places like schools, where kids need to learn, teachers need to teach." 

After more than a week, temporary window air conditioning units were installed at the school.

"Many schools are already facing challenges in so many areas, AC shouldn't be one of them," Barrett said.

The hot weather has spelled trouble for school districts nationwide. In the first week of September, schools in nine states — Michigan, Ohio, Wisconsin, Maryland, Connecticut, New Jersey, Pennsylvania, Virginia and Massachusetts — have either been closed or dismissed students early because of the heat.

According to a 2021 report from the Centers for Climate Integrity, close to 14,000 public schools that didn't need cooling systems in the 1970s will need them by 2025, at an estimated cost of almost $40 billion.

In Baltimore, no central air conditioning in some schools forced students back to remote learning.

"Everybody should have air," a parent told CBS Baltimore. "You have air in your car, air at your job, why not at schools?"

In Philadelphia, 57% of schools don't have adequate cooling, according to Philadelphia School District officials. As a result, 86 schools are dismissing students early for the rest of the week.

"It's so humid, the cafeteria, it's like this huge cafeteria, there's no air at all," one student said.

In:
• heat
• Education
• Heat Wave

Christina Ruffini

CBS News correspondent