Most people know that black absorbs heat and white reflects it, but what about all the colors in between?
Toshiaki Ichinose, a Senior Researcher at Japan’s National Institute for Environmental Studies, has conducted an experiment to gauge which colors of clothing will keep your body the coolest under the sun. Ichinose explains that objects reflect radiant energy from the sun at different rates depending on color. The unreflected energy is absorbed in the form of heat, and therefore objects with higher reflecting colors are cooler.
Ichinose and his team conducted an outdoor experiment under the searing summer sun at a temperature of 30 °C (86 °F) with little to no wind. Nine different colored polo shirts of the same material were placed side by side and monitored via a heat camera for 5 minutes. The results found that the coolest shirt was white, followed by yellow, gray, red, purple, blue, green, dark green, and black in that particular order. The temperature difference between the shirts was quite drastic, with the white shirt registering 30 degrees Celsius (86 degrees Fahrenheit), and the dark green and black shirts registering above 50 degrees Celsius (122 degrees Fahrenheit).
“If you don’t like white shirts because they are easy to get dirty, we recommend yellow, gray, and red shirts that have relatively high reflectance,” says Ichinose on preventing heatstroke.
Head to the 1:11 mark on the video to view the heat map of the polo shirts.