This story is part of a collaborative reporting project led by the Institute for Nonprofit News and including Borderless Magazine, Cicero Independiente and Inside Climate News. It was supported by the Field Foundation and INN.

TEMPE, Ariz.—It was just before 8 a.m., yet the temperature was already nearing 100 degrees Fahrenheit as members of Arizona State University’s SHaDe Lab lugged a ladder and their heat-measuring equipment to Kiwanis Park.

Nobody else was at the playground but one child coasting down a slide and her mother. Across the street at the local elementary school, the principal could be heard giving his morning address over the PA system: “Another heat advisory today,” he warned. “I saw a group of girls having some nice conversation in the shade yesterday and I encourage you all to do the same.”

It’s an issue across the country, as climate change has led to 14 straight record-high monthly global temperatures, with Midwestern cities like Chicago seeing an unprecedented heatwave in August. But it is especially pronounced in places like the Phoenix metro area, which includes Tempe. Heat is a constant fact of life here—and a present-day peek into other communities’ future. Already, cities from New York to Los Angeles are rethinking playground design.

“Playgrounds are really at the heart of extreme heat impact,” said Ariane Middel, the SHaDe Lab’s director and an associate professor focused on the intersection of extreme heat and urban climates, including at playgrounds in the Phoenix area.

“Kids don’t really care about sun or shade or heat, they just want to play, so they don’t pay attention,” she said. “But then the second issue that we have with playgrounds here in Phoenix, where there’s an absence of shade, is the surface temperatures. Because kids usually use their bare hands, they’re barefooted, and these surfaces on playgrounds get really super hot.”

Shade, Middel said, can make all the difference. Whether from trees or large engineered shade structures, like shade sails and permanent canopies, playground equipment covered from the sun stays consistent with the air temperature around them. 

Nationwide, shade is not distributed equally. Wealthier communities often have more, researchers have found. Solutions to addressing heat also vary across the country. In Chicago, for example, shade is helpful, but wouldn’t help address the city’s summer humidity, Middel said, meaning there is no one-size-fits-all approach to addressing climate change’s impacts on playgrounds.

A better understanding of shade could still have big ripple effects. For years, the playground at Kiwanis Park has been under the cover of a shade sail, with trees surrounding the site, making it an ideal location to study how shade can impact the ways people interact with their surroundings.

How Researchers Are Measuring Shade’s Impact on Extreme Heat

At Kiwanis Park, the lab has installed three weather stations at one playground. Called “MaRTinies” and pronounced like the drink, they’re named after the lab’s mobile MaRTY device, key to its research on mean radiant temperature. That single number highlights how radiation from the sun and the hot surfaces around an individual influence the heat that a person feels in the moment.

MaRTY costs about $20,000 and needs to be wheeled around in a large cart, whereas the MaRTinies, white boxes hooked up to tiny solar panels, are just a fraction of the size and expense. They measure temperature, humidity and the mean radiant temperature, and, with a camera, count people, showing how playground use changes with weather and shade conditions. Every minute, the data is uploaded to the lab’s servers. 

“We can look at the data across the seasons, across different temperatures, across weekends versus weekdays, across different times of day, and see how the space use changes,” Middel said, allowing the city to “know how their playgrounds are being used” based on the weather and shade being provided. 

The monitoring began in April. Researchers need more months of data before they can issue findings, including how people’s use of the park changes as the temperature drops.

At the playground, Pouya Shaeri scaled a ladder as Ameya Ajitraj Shahane handed him tools and equipment, a process the two graduate students with the lab have done throughout the summer to keep the mini weather stations operating smoothly. Unsurprisingly, the harsh temperatures in the Valley of the Sun can impact the MaRTinies as they measure the heat, draining their batteries and requiring frequent checkups. 

The very thing the lab is studying—how extreme heat and shade levels affect people’s interactions with their environment—in turn impacts the equipment to measure it. 

“The goal of this study is causing the problem,” Shaeri said.

Shade Key to ‘Healthy, Vibrant Existence’ in the Desert

In Tempe, the city maintains a shade canopy coverage of around 25 percent at all of its parks, said Richard Adkins, the city’s urban forester tasked with meeting Tempe’s goal to have that level of shade coverage across the entire city by 2040. Parks and playgrounds have been a major focus area for expanding shade, as those sites are owned by the city, making it easier to plant there than at private residences and businesses. 

The job is not as simple as just planting trees and calling it a day, he said. Plants need to be maintained or they will die. The city’s current tree population is beginning to age out, with its large pines not able to survive the city’s rising heat. And trees can’t be planted just anywhere: Planners have to think about the use of the area and how shade fits into it. 

“I’ve got a lot of soccer fields at the sports complex [where] I could plant many thousands of trees,” Adkins said. “But then again, that goes against playing the game of soccer.” 

Another consideration: Some trees shed their leaves for the winter months, but materials like those found at playgrounds can quickly heat up even when it’s colder.

Adkins has prioritized planting smaller trees adapted for the desert Southwest and implementing more man-made shade, like the shade sails found at many of the city’s playgrounds. 

There, the focus is typically an engineered shade structure covering the playground and its equipment, helping to keep it all cool and also preserve the materials. Trees planted around that area provide cover for the walkways and benches where parents typically sit. Every day, he’s in touch with heat and shade researchers like Middel to find new solutions to the problems.

Extreme heat is here to stay, Adkins said, and shade, both from trees and engineered designs, will be vital for mitigating it. 

“That’s the only way that we’re going to have a healthy, vibrant existence moving forward here in the desert Southwest,” he said.