Which color shirt might be best to wear outside on a hot day to stay cool, and why?

Red, because it reflects heat and light.
White, because it reflects most of the light and does not get hot.
Black, because it absorbs all light and heat.
Blue, because it absorbs heat and light.

White would be the best color to wear on a hot day to stay cool. This is because white reflects most of the light and does not absorb heat like darker colors do. When sunlight hits a white fabric, it reflects a majority of the light away, reducing heat absorption and keeping you cooler. On the other hand, black absorbs all light and heat, making it the color that retains and traps the most heat. Therefore, wearing a white shirt would help in staying cooler on a hot day.