When the weather’s hot, it can be hard to concentrate and learn. And research suggests that as the number of hot days increases, student achievement may suffer.

“The adverse effects appear to accumulate over time,” says Jisung Park, an assistant professor at the University of California, Los Angeles. “It’s almost like a death by a thousand little cuts.”

Park’s team examined standardized test scores from 12,000 U.S. school districts over seven years. They also looked at local temperature data for each district.

They found that in years when a school had more hot days than normal, average test scores declined. But the drop affected some demographic groups more than others.

“The effect of heat on learning appears to be far more pronounced for low-income students as well as for under-represented minorities, so African-American and Hispanic students.”

One reason for the disparity is that schools in low-income areas often lack air conditioning. So Park says that as the climate warms, the inequity in education could grow.

“But on the flip side, our study also suggests that investments such as school air conditioning … could prevent a lot of that adverse impact,” he says.

So those investments would help students concentrate on their studies instead of the heat.

Reporting credit: Sarah Kennedy/ChavoBart Digital Media.