The air temperature is measured by means of thermometers. Weather reports usually indicate the maximum and minimum temperatures expected for a given period.
Water vapor in the air helps retain heat. Thus we find that in drier places there is less heat retention in the atmosphere and the difference between maximum and minimum temperature is greater. Simply put, we can say that in these places can be very hot during the day, thanks to the sun, but cold at night as, for example, in the deserts and caatinga.
Typical desert clothing is usually wool, a great thermal insulator that protects it from both cold and excessive heat. In addition, the clothes are well loosened on the body, with enough space to create thermal insulation.