>>212018040 (OP)1. Prevent skin cancer - The reason why the clothing in that part of the world covers head to toe is because they learned exposure to the sun causes skin cancer. It's also why men grow beards, and women wore veils in order to protect the face.
2. Haboobs - Sand storms can come out of nowhere, and the head to toe covering helps keep the sand from inhabiting every crevice of your body.
3. Air circulation - The loose clothing they wear helps air to circulate over the body, which helps evaporate sweat, increasing cooling.