Beating the Heat

TOP 2024 TEMP: 99°F*
COOL TOOL: Chill Clothes

Facing a sticky day in Japan’s capital? You don’t need to head inside to cool off. Just slip into an air-conditioned outfit! It may sound like sci-fi, but many people in Tokyo already dress in clothing designed to keep them cool. The garments feature small battery-powered fans that draw air inside the fabric. The circulating air evaporates sweat, which helps lower body temperature.

Tokyo experiences serious heat waves during the summer months. A local engineer pioneered the wearable tech in 2004 to provide relief for outdoor workers. Today delivery drivers and construction crews in the city often sport air-cooled uniforms in light, breathable fabrics. The trend has breezed beyond workwear too. Japanese fashion designers are incorporating fans into jackets, shirts, and vests. At a recent runway show in Paris, France, models strutted in giant cloudlike dresses inflated by hidden fans.

Japan’s air-conditioned clothing industry is worth more than $100 million domestically—and growing. For now, though, the pieces can be expensive and hard to find outside Asia. Still, the designs hint at fashion’s future: dressed to chill.

TOP 2024 TEMP: 98°F 
COOL TOOL: Smart Schoolyards

Imagine if your schoolyard went from paved to paradise. That’s the idea behind a growing effort in Paris, where experts predict up to 25 days of extreme heat a year will be the norm by the end of the century.

Many school playgrounds in the city are covered in asphalt or dark concrete. Those materials make the surrounding space feel even hotter. That increases the risks of heat-related illness for kids and teens playing there.

So, in 2017, Paris launched a project to transform its schoolyards into cooler, greener spaces. Light-colored gravel replaced pavement. Trees, gardens, and fountains were added. Many of the redesigned play areas open to the public after school and during heat waves so more people can benefit from them.

So far, 165 schoolyards have been renovated. Paris aims to redo 360 more by 2030. Meanwhile, the U.S. and other countries are also reimagining schoolyards to help fight extreme heat and preserve play.

TOP 2024 TEMP: 93°F 
COOL TOOL: Heat-Smart Markets

People buy food and other goods at busy outdoor markets in Freetown. But the merchants selling those items also pay a price. The workers, mostly women and girls, spend long hours on their feet in the scorching sun. The heat can make them ill. It also hurts their business: The meat, fruits, and vegetables they sell spoil quickly.

Freetown’s solution was to block the sun. In 2022, the city received funding from a nonprofit to build canopies that help shade three outdoor markets. After testing several designs, the city is now installing shade covers made from fabric that reflects sunlight and helps keep things underneath it cooler. The tough material is also waterproof to withstand the area’s heavy rains.

When the project is completed in 2026, more than 2,300 merchants in Freetown will be under cover. And the program may end up benefiting people far beyond the outdoor markets, notes scientist Cassie Sutherland of C40 Cities, a global environmental group. Other places can learn from Freetown’s example, she says. “It’s great for other cities to be able to implement solutions faster.”

TOP 2024 TEMP: 118°F 
COOL TOOL: Artful Shade

Heat has long been a part of life in Arizona’s capital, but it’s getting worse. In 2024, Phoenix hit a record: 70 days at or above 110°F.

The blazing sun makes the city’s public parks nearly unusable. Keili Lopez Pastor, 17, lives across from one of them. “For the past couple of years, it’s been too hot to be outside,” she says. “Sometimes it even feels too hot to be inside!”

This past April, the city began testing a creative solution: colorful shade structures that double as public art. The large-scale sculptures now offer relief in nine parks across the city. At one park, people can relax under a fabric tunnel made from recycled clothing and bedding. At another, a model of a giant desert tortoise casts a welcome shadow.

Thermal imaging shows the shaded spots under the sculptures are up to 25°F cooler than the areas outside them. Keili is already feeling more comfortable at her neighborhood park. There, painted panels inspired by Mexican folk art are paired with a solar-powered misting system. Keili and other students from nearby Alhambra High School helped paint the colorful panels. “Thanks to this structure, I’m able to go outside and not just see the park but actually use it,” Keili says.

The temporary installations are set to come down this fall, but Phoenix officials hope to eventually build more permanent structures at the parks, says Carrie Brown. She’s part of the city’s Arts and Culture department. 

“This project is about trying new things and sparking dialogue,” Brown says. “And I think that’s really valuable when you’re tackling a big issue like heat.”

TOP 2024 TEMP: 97°F 
COOL TOOL: Green Streets

Medellín’s location high in the Andes Mountains once provided weather in the mid-70s all year long.

But starting in the early 2010s, Medellín began experiencing unusual temperature spikes. Some experts blamed rapid development. Over the years, roads and buildings had squeezed out trees and parks in some neighborhoods.

In 2016, Medellín’s leaders took bold action. They launched a $16 million project to plant trees and other vegetation along roads, sidewalks, and riverbanks. The idea was to connect existing parks and other green spaces across the city by growing plants along the hot, paved areas in between. Vertical gardens were even added to the sides of buildings, bridges, and other surfaces.

The newly planted areas became part of what the city calls “cool corridors.” Today 30 of these shaded routes crisscross Medellín, bursting with more than 2.5 million plants. Local workers tend to the gardens.

Even though the city still experiences some hot days, its average temperature has dropped by about 3.6°F and local air quality has improved. And to top it off, Medellín’s green movement is spreading. Similar programs are taking root in other Colombian cities.