Summer is the hottest of the four temperate seasons, falling after spring and before autumn. This season is usually associated with warm or hot weather. Typically, schools and universities have a summer break to take advantage of the warmer weather and longer days.
During summer, we normally wear light coloured cotton clothes. We sweat a lot in summers. Cotton is a good absorber of water.
Thus, it absorbs sweat from our body and exposes the sweat to the atmosphere, making its evaporation faster. During this evaporation, particles on the surface of the sweat gain energy from our body surface, making the body cool. Further light coloured clothes are poorer absorber of heat and would be better for summer. We wear different clothes during different seasons in order to adjust to the changing atmospheric conditions.
Below is an interesting video talking about how clothing make into existence: