These psychedelic images reveal what your weather app isn’t telling you

A researcher in Portland used an infrared camera and a car-mounted sensor to measure how much hotter cities actually feel compared to the temperature on a weather app. On an 80-degree day, artificial turf hit nearly 150 degrees, while nearby natural grass measured around 100. Sunny pavement reached the mid-130s, dropping 50 degrees in shaded spots. Highways ran about 120 degrees from vehicle friction and engine heat, while shaded greenery nearby stayed in the mid-80s.

Driving across the city, temperatures swung by several degrees block to block — cooler in tree-lined neighborhoods, hotter in areas with wide roads, short buildings, and little shade. Trees cool the air by releasing water vapor, while pavement and turf absorb heat during the day and release it at night, so treeless areas stay hotter even after sundown. Lower-income neighborhoods tend to have the least tree cover, meaning residents there face both worse daytime heat and less overnight relief. The gap between the hottest and coolest neighborhoods grows on more extreme days — from a few degrees on a mild afternoon to over 20 degrees during a heat wave.

For homeowners, the takeaway is that shade and greenery on your own property, or lack of it in your neighborhood, can mean a real difference in how hot your house and yard get. Trees, lighter-colored surfaces, and shaded walkways all measurably lower temperatures, while artificial turf, dark pavement, and open lots trap and radiate heat well into the evening.