Snow day, meet heat day: Summer weather takes bites from school calendars

The ritual of snow days is a beloved part of American childhood. Kids wake up on winter mornings with frost in the air and ice on the roads and anxiously check to see if school was canceled or delayed. 

But now, summer is chipping away at the academic calendar too: Heat days are taking their toll. Hundreds of schools across the country have started out their school year by promptly shutting down due to extreme August weather fueled by climate change.

“Milwaukee Public Schools will be closed tomorrow, Wednesday, August 23, 2023, due to an excessive heat warning for Milwaukee County,” the school district said Tuesday as temperatures reached the upper 90s in the area. 

In the past few years, heat days have become more common near the end and beginning of academic year as temperatures climb and schools lack the proper infrastructure to handle the change. 

“The heat wave season is getting longer. The average length of the annual heat wave season in the 1960s was maybe 25 days, and now it's over 70 days. And then, the intensity, the average temperatures are getting hotter,” said Jan Carney, the associate dean for public health at the University of Vermont. 

Milwaukee alone had 154 schools shut down for heat, affecting almost 70,000 students. Des Moines Public Schools, which serve 33,000 students, closed three hours early on Thursday due to high temperatures. States including Kansas, Missouri, Illinois and Ohio have also seen schools close due to heat this month.

In 2020, the Government Accountability Office published a report that found 41 percent of U.S. schools do not have proper heating, cooling and ventilation systems in their buildings. 

“There's an opportunity right now for schools that want to make these investments to utilize funds from the Inflation Reduction Act to do so and get tax credits that are available to help reduce the costs of adding these cooling systems,” said Laura Schifter, who leads This is Planet Ed at the Aspen Institute. 

Schools are going to have to work quickly as studies are showing that hotter temperatures can lead to decreases in test scores and long-term learning. 

It is difficult to say if climate change is also fueling a drop in snow days, particularly since, in the wake of the pandemic, many districts now simply shift to remote learning when the weather is rough.

“I would say any signal of reduced closures due to snow is buried in a wealth of variables out there,” said David Robinson, head of the Global Snow Lab at Rutgers University and a New Jersey state climatologist, pointing to well-established local resources to deal with snow on the roads and a superintendent's judgment call in canceling classes. 

While the South has been seeing less snow generally than in years past, communities further north could actually end up getting more snow in the future, according to Robinson. 

“How come we're not seeing less snow? [...] Further to the north, even though it's warming up, it's still cold enough to snow when these systems come through. There may be snow that may stay on the ground a shorter period of time and may melt faster, but when these precipitation events come through, it's still cold enough to snow,” he said. 

“The fact is it's still below well below freezing, but as the air gets milder it can hold more moisture [...] It is still cold enough to snow and with the warmer temperatures it can snow more,” Robinson added. “Until you are consistently above that freezing point, you can still get snow storms and you might get bigger ones because you're working with more moisture at sub-freezing temperatures.”

Still, it's possible that for many districts in the future, more classes will be canceled for high temperatures than blizzards.

“Are these heat days becoming the new snow days? And my answer to that is yes,” said Carney of the University of Vermont.

“The seasons are lasting longer, and we need to prepare at the moment and both for individuals and our communities. And then also, of course, support policies that help this in the long term,” she added.