New study: Urban schools across US facing extreme heat 

By Stefan Hagens, The Invading Sea   

As climate change drives warming temperatures, children in cities are feeling the heat – with urban infrastructure intensifying heat risks in classrooms across the U.S.

Urban heat islands are developed areas that are hotter than natural landscapes. The heat-absorbing qualities of infrastructure, lack of vegetation and excess heat from human activities are all driving forces of the higher temperatures.   

New research from the nonprofit organization Climate Central looks at the impacts of this phenomenon on K-12 schools in the 65 largest cities in the country. Extreme urban heat zones – areas that are warmer by 8 degrees F or more due to the built environment – were found to be affecting 76% of children in the study. This percentage is equivalent to nearly 4.7 million students nationwide.

“Anywhere you have excess development and lots of people, it’s going to be hotter. … Children are at increased risk, particularly from higher temperatures,” said Jen Brady, a senior data analyst at Climate Central.  

Three Florida locations – Orlando, Tampa and West Palm Beach – ranked among the top 10 U.S. cities with the highest percentage of students in extreme urban heat zones. In Orlando, a staggering 97% of students – or more than 43,700 students – attend school in these areas.  

West Palm Beach and Tampa are not much further behind at 95% and 92%, respectively. Other Florida cities in the study included Fort Myers/Naples (86%), Jacksonville (72%) and Miami (55%).  

Brady believes that Florida’s continued development to meet housing and infrastructure needs leads to these conditions.  

“Along the southern tier of the country we’ve seen tremendous population growth and expansion, where the growth doesn’t really consider things like heat,” she said.    

Increased temperatures in urban areas are the source of a range of environmental and public health concerns. Extreme heat increases the risk of heat-related illnesses such as heat exhaustion and heatstroke, which can have a greater impact on more vulnerable populations. 

“Children and elderly are most at risk. We do find that lower-income populations tend to live in neighborhoods that tend to have higher urban heat islands across the country,” Brady said.

Brady said that part of her work at Climate Central is to pinpoint the areas that are most in need of help. By showing communities where risk is the highest, adaptations can be made to effectively protect people.  

“In a lot of ways, schools are little urban heat islands … and then when they are within a larger urban heat island, you’re talking about an area where kids can’t get out of the heat,” Brady said.  

Schools and other affected areas can implement changes to reduce temperatures, varying from simple solutions to high-tech improvements. 

Brady suggests making changes as small as adding shade structures or reducing playground blacktop use, which can help reduce the heat while larger-scale solutions are being put into place. When adding natural areas isn’t an option, these improvements can include using reflective pavement, white roofs and vegetation on roofs — all of which retain less heat in the urban environment. 

Urban heat islands contribute to more energy consumption for cooling purposes, causing elevated pollution and greenhouse gas emissions. Air conditioning alone accounts for a significant amount of energy usage in the U.S. and abroad. 

“It’s a terrible irony that making our life more livable is actually contributing to the problem,” Brady said.  

This contributes even more to the urban heat island problem and consequently worsens the effects of climate change.  

“It’s additional heat on top of what we’re already feeling from climate change,” Brady said. 

Stefan Hagens is a junior majoring in environmental engineering at Florida Atlantic University who is reporting for The Invading Sea during the summer 2025 semester.

Sign up for The Invading Sea newsletter by visiting here. To support The Invading Sea, click here to make a donation. If you are interested in submitting an opinion piece to The Invading Sea, email Editor Nathan Crabbe at ncrabbe@fau.edu. To learn more about the urban heat island effect, watch the video below.