WASHINGTON — Rising temperatures are widening the racial achievement gap in U.S. schools, new research suggests, offering the latest evidence that the burdens of climate change fall disproportionately on people of color.

In a paper published Monday in the journal Nature Human Behavior, researchers found that students performed worse on standardized tests for every additional day of 80 degrees Fahrenheit or higher, even after controlling for other factors. Those effects held across 58 countries, suggesting a fundamental link between heat exposure and reduced learning.

But when the researchers looked specifically at the United States, using more granular data to break down the effect on test scores by race, they found something surprising: The detrimental impact of heat seemed to affect only Black and Hispanic students.

R. Jisung Park, the paper’s lead author and an assistant professor of public policy at the University of California, Los Angeles, said the gap seemed to reflect the fact that minority students are less likely to have air conditioning at school and at home. Being exposed to higher temperatures throughout the school year appears to take a gradual and cumulative toll on those students’ ability to absorb their lessons, he said.

“It’s like a thousand little cuts to your ability to focus and concentrate and learn,” Park said.

The findings are the newest addition to a growing body of research showing that climate change in general, and rising temperatures in particular, have a greater effect on minorities.

A study published in January found that a history of redlining — the long-discredited policy of marking minority neighborhoods as risky places for banks to lend money — and the underinvestment that goes along with it has left many Black neighborhoods today with more paved areas and fewer trees. As a result, those neighborhoods were hotter than their white counterparts, leading to more cases of heat-related illnesses.

In June, research published in JAMA Network Open showed that pregnant women exposed to high temperatures or air pollution are more likely to have children who are premature, underweight or stillborn, and African American mothers and babies are harmed at a much higher rate than the population at large.