Help prevent seasonal affective disorder (SAD) later by soaking up extra sun now. The more vitamin D you absorb in the summer, the higher your seratonin levels in the winter, researchers discover. 

Sunbathing dramatically reduces the risk of several types of cancers, autoimmune diseases, bone diseases, type 1 diabetes, depression, and, in proper doses, can even reduce the risk of melanoma, a meta-analysis of sun-related-disease studies finds