Question

why do people in desert area wear white robes

Answer 1

The outer layer of fabric does get hotter because the black color absorbs more heat. And that heat doesn't get transmitted to the skin because of the thick fabric. But thin black clothing transmits that heat to the skin, making a person hotter.

Answer 2

As white color is the best reflector of heat . so heat is reflected when it incidents on white robe and heat is absorbed in very little quantity