Anyone who has been out in the sun in a black t-shirt has likely noticed that sunlight makes the shirt get hotter and hotter under the sun. If you’ve worn a white t-shirt, you may have noticed the opposite effect and how cool it kept you. You might have also left a white t-shirt out in the sun and felt that it was a little warm when you picked it up. If you leave a black t-shirt out in the sun, however, it will feel far hotter when you pick it up. That is because of the way light is absorbed or refracted by different colors.

The darker the color of the t-shirt, the more light the t-shirt will absorb. This is why a dark t-shirt will heat up in the sunlight- it is absorbing the light of the sun. And along with the light of the sun comes the heat of the sun. So, the longer the t-shirt is out in the sunlight, the hotter it’s going to get. A black t-shirt is the darkest color and will therefore get hotter than any other color t-shirt.

A white t-shirt works very differently. The color white actually deflects light and heat away from it. It doesn’t absorb light and heat the way that other colors do. Wearing a white t-shirt will always keep you cooler than wearing a darker-colored one. If you will be outside in the sun for a long time, wearing a white t-shirt is a good way to keep cool. It will probably keep you cooler than if you weren’t wearing a shirt at all.

If you wear a black t-shirt out in direct sunlight for any length of time, especially, if it’s a hot day, you will likely become extremely uncomfortable. If you know you will be in the sun all day for a specific activity, plan ahead by choosing to wear a white t-shirt for the day. Even if the t-shirt doesn’t go as well with the rest of your outfit, it will keep you far more comfortable. After a few hours in the sun in a black t-shirt, you may stop caring about how the outfit looks and wish you had instead chosen the cooler t-shirt.

If you will be outside without water, it’s even more important to make sure that you are wearing a white or light-colored t-shirt. It will cause you to sweat less under the sun and you will lose less of your hydration.

The way that a black t-shirt and a white t-shirt absorb heat and light will also factor into how long it takes each of them to dry. Sweat is produced by the body in order to keep the body cool. But, if you sweat on a hot day in a black t-shirt, that sweat will evaporate quickly- possibly before it even has a chance to cool down your body temperature. In a white t-shirt, however, it will not evaporate as quickly and you will have the benefit of letting it cool you down.