As Students Return, America’s Classrooms Are Dangerously Hot

A fan moves air around in a classroom at Corey Elementary in Denver, Colorado on October 8, 2024. —RJ Sangosti—The Denver Post As students go back to school in the midst of record-breaking summer heat , many are returning to overheating classrooms whose aging air conditioning systems can't keep up with extreme heat waves—if they even have air conditioning at all.

Extreme heat has already caused school closures and disruptions across the country.

In July, Milwaukee Public Schools shut down its Summer Academy and other indoor school programs for two days because of extreme heat.

One day in May, 57 Philadelphia schools went remote and canceled all in-person activities due to soaring temperatures.

That same month, a Washington, D.C. high school carried out a "heat evacuation" as classroom temperatures reached the mid-90s.

Eight elementary schools in Doylestown, PA also closed for a day because old buildings couldn’t protect students from the heat.

And in recent years, schools in Memphis dismissed students early as temperatures climbed to 110 degrees.

During the 2024-25 school year alone, more than 9 million students at 10,000 schools nationwide experienced extreme heat- and weather-driven school closures or disruptions.

These are not isolated inconveniences.

They are warning signs that our school buildings and grounds were not designed for today’s new weather patterns.

It’s important to understand that students struggle to learn in hot, stuffy classrooms.

Air quality, temperature, and ventilation can affect how students think, focus, and perform.

Poor ventilation can impair cognitive function , while excessive heat diverts the body’s energy from learning, slows reaction time, and weakens attention.

In fact, research has shown that in schools without cooling, each 1° Fahrenheit increase in school year temperature reduces the amount learned that year by approximately 1%.