Extreme heat is making it harder for kids to learn

Each year, schools around the country spend the last weeks of summer break preparing for the day when promising young minds flood through their doors. Yet educators and policymakers too often overlook a crucial step in helping children thrive: developing a plan for extreme heat.

The need is becoming more urgent as climate change makes sweltering school days more common. The number of extremely hot days — when the heat index hits 90F (32.2C) or more — has been rising across much of the U.S., a four-decade analysis of more than 300 American cities found. Worse, extreme heat is arriving earlier in the season, ending later, and lingering longer.

As those high temperatures increasingly encroach upon the school year, districts aren’t adapting fast enough. That’s in part because many parents, teachers and administrators aren’t even aware that very hot days can hurt kids’ health and ability to learn.

"When people think about heat, they think of it as a comfort problem," says Nicole Barnes, executive lead psychologist for the American Psychological Association. Earlier this month, the APA put out its first-ever report on extreme heat and schools, finding that the consequences go far beyond feeling sweaty. Spiking temperatures affect children’s cognition, attention, concentration, behavior, and physical and mental health.

That shouldn’t be surprising. Surely adults can relate to the misery of trying to stay awake in a conference room when the air conditioning is on the fritz, or of feeling less patient with co-workers after a sweltering commute. So it’s no stretch to imagine kids having a hard time focusing on algebra — let alone using their developing emotional-regulation skills during a heat wave.

Until recently, there wasn’t much concrete evidence to back up the intuitive sense that heat could disrupt learning. But researchers have found clever ways to comb through datasets for answers.

For example, when R. Jisung Park was a graduate student at Harvard University, he helped analyze millions of scores on Regents exams — the end-of-course tests taken by New York high-schoolers. Because those tests are given at set times, he could estimate the conditions under which students took them. That allowed him to compare the same student’s performance across multiple testing days — some hotter, some cooler.

Park, now an assistant professor at the University of Pennsylvania, found that high-school students in New York City were roughly 10% more likely to fail a Regents exam on a 90F (32.2C) day than on a 72F (22.2C) day.

He and his colleagues later used similar methods to look at PSAT scores for students across the US. They found that student performance faltered in hotter-than-average school years, with each degree Fahrenheit above average leading to a roughly 1% reduction in learning, as measured by PSAT performance.

Of course, the problem starts much earlier than high school. A separate study used reams of data from six countries to understand whether unusually high temperatures affect children’s development. When temperatures rose above regional averages, preschoolers were less likely to be developmentally on track, explains Jorge Cuartas, a psychologist and economist at Colombia’s Universidad de los Andes who worked on the study. The effects showed up in language and math skills as well as other cognitive processes. Unsurprisingly, they were worse among kids from poorer households.

The worry is that those adverse effects will cascade as kids get older. The cognitive and socio-emotional resources built in early childhood lay the foundation for more advanced skills, Cuartas explains. Extreme heat could leave some kids — especially the most vulnerable children — always playing catch-up.

As the evidence increasingly points to the very real impact of heat on kids’ ability to learn, society needs to better adapt. The APA suggests parents, schools and policymakers should "treat heat as a snow day for cognition."

Before everyone gets in a tizzy over the specter of school closures, understand the goal is to raise awareness and build adaptations into the system — not shut everything down.

That starts with evolving beyond simple solutions. Ensuring classrooms are cool — the go-to reaction from most districts — is only part of the puzzle. "A district can have air conditioning, but still have weak heat planning," Barnes says.

What would a more robust response look like? The first step should be to determine what temperatures count as "extreme" and to develop an adaptation plan that every teacher, coach and staff member can follow.

Such a plan must consider the broader learning environment of a school and how it affects a student’s physical and mental well-being. As I’ve seen in schools here in Chicago, individual classrooms might have AC, but common spaces like lunchrooms and gyms can be broiling, and playgrounds lacking in shade entirely.

And a good plan should identify groups that are more vulnerable to the heat and make sure measures are in place to help them. For example, some children don’t have AC at home and will be sleeping poorly, while others might have spent an hour on a hot bus to get to class. And some students — and, by the way, staff and teachers — have health conditions or take medications that worsen heat’s effects.

Schools already adjust or cancel sports practices when it’s too hot out, so why not adapt academics for the heat, too? For example, schedules could be modified so that the most challenging classes are packed into the morning, before the most punishing heat sets in. And, as the APA points out, state education agencies should factor in the potential for extreme heat as they plan standardized tests — and consider rescheduling high-stakes exams on days when student performance could dip.

Educators and parents might not be able to manage the temperature outside or convince policymakers to take climate change seriously. But they can absolutely control expectations placed on kids on a hot day — and do everything possible to limit heat’s impact on their academic and emotional development.

This column reflects the personal views of the author and does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners. Lisa Jarvis is a Bloomberg Opinion columnist covering biotech, healthcare and the pharmaceutical industry. Previously, she was executive editor of Chemical & Engineering News.