Shade in the desert is important, because you need to keep your core temperature down, and protect yourself from sunburn. A hat can keep you cooler as well as shade your eyes from the sun. Your eyes are sensitive to the sun and can be damaged by long term sun exposure. The sun can get around the sides of your sunglasses depending on the angle, while a hat can block the sun in addition to your sunglasses. The sun can also damage your skin and hair. Long term exposure to the sun can cause wrinkles and sun spots. Protect yourself, wear a hat!