UPF clothing helps block, absorb, and reflect UV radiation to reduce the skin’s exposure. UPF ratings range from 15 to 50+ UPF—with a UPF 50 rating meaning only 2 percent of the sun's UV rays can pass through the garment and reach the skin’s surface. Dark and brightly colored garments work best by absorbing UV rays, keeping them from penetrating the fabric and reaching the skin’s surface. Additionally, loosely fitted UPF clothing is preferred, as tight clothes stretch the fibers which make the garment lose effectiveness. Overall, the higher the UPF rating, the better the protection. When in doubt, choose UPF 50+ clothing.