What is true about black and white shirts in the summer?

No color is absorbed by a white shirt but instead it reflects all the colors in the spectrum of light while a black shirt absorbs all the color in the spectrum of light.

Black absorbs heat while white shirt reflects it.

Explanation:

During the Summer it is considered to wear a white shirt because it white reflect light and keep out body temperature in normal without adding any outside heat from surrounding. The black color shirt is not much preferable because it absorbs the heat and light without reflecting it back. Black absorbs everything coming in from the sun, also absorbs energy from the body.