'Cool Routes' finds cooler walking paths with hourly forecasts and street-level shade data

[erronis]

https://phys.org/news/2026-06-cool-routes-cooler-paths-hourly.html
Arizona State University

To validate the predicted heat loads, researchers used MaRTy, a rolling instrument station that measures human thermal exposure and other meteorological data. Credit: Ariane Middel/Arizona State University

The Arizona sunshine hits like a blowtorch. The pavement radiates heat like a stove burner. To make hot-weather walking less of an ordeal, Arizona State University researchers have created a web-based app that finds the coolest, shadiest ways to reach destinations on foot.

Cool Routes, the online tool developed by Ariane Middel and colleagues in The SHaDE Lab at ASU, chooses paths based on forecasts of mean radiant temperature, a measure of the total heat load experienced in a given location, including reflected heat and sun exposure.

"It's more comprehensive than just using air temperature or land surface temperature," said Middel, an associate professor in The GAME School at ASU.

In sun-blasted Phoenix, the mean radiant temperature can exceed 150 degrees Fahrenheit in full sun but drop below 100 degrees Fahrenheit in the shade. Shade can make a real difference in people's heat exposure on a hot, sunny day. Cool Routes updates itself with hourly meteorological forecasts and works with detailed building and tree data to compute sun exposure and location-specific mean radiant temperatures on a map.

. . .

I've spent a lot of time working in Phoenix where it is a mad dash from one AC place to another (when possible.) This sound like a good idea.

[Botany]

1. R you kidding me?

Telling people to walk in the shade, to avoid heat sinks like blacktop and concrete, and to stay
out of the direct sun when it is very hot does not need a University study.

[erronis]

2. I think this is meant to be used as a way of finding these paths in the shade.

Appreciate your concern....

[Torchlight]

3. I'd wear it out during a TX summer

Aug-Oct often feels unbearable, and even our morning walks can be sweltering. Living in a small, two stop-light town, driving from A to B seems almost excessive when it's only a mile away, but on a 110+ day, I rationalize my laziness. Something like this might see me do that less.

[pecosbob]

4. When I lived in San Francisco I used to have a bicycling map that showed all the street grades.

All city blocks were marked either in white, pink or red...I learned to avoid the red blocks.

[electric_blue68]

5. How clever, and smart of them!

Funny little tale.... and loved my visit to SF decades back!

I was going up the steeper kind of a mid grade hill; walking probably towards a bus to get back to my hotel in the evening. It was summer time.

I kept feeling these teeny little "pings" of mousture on my skin. ??? Eventually they stopped.

Quite later on, I figured out I must have been in a very light fog. Usually you know when you're in a fog, but I didn't.

[erronis]

7. Glad you enjoyed the fog effects. (It also could have been droplets from AC units above....)

[hunter]

6. It's possible to make "cool routes" using native plants.

Phoenix needs to pay attention to this group:

Tucson is the third fastest warming city in the U.S., but we can reduce urban temperatures by over 10˚ F degrees in the shade of native vegetation.

By planting the rain and multi-use native vegetation, hot and exposed public rights-of-ways can become cool and shaded, food-producing public forests that shelter and enhance public walkways and streets...

https://dunbarspringneighborhoodforesters.org/

This is something everyone living in hot dry places should consider.