Clouds do not screen out all UV radiation. Also, sand, snow and water reflect UV radiation, which means being in the shade under a beach umbrella does not provide complete protection. Wearing a hat with a wide brim is a good idea to protect the eyes, ears and neck. Most clothing, except white, reflects or absorbs the radiation, but wet cotton, no matter what color, can let a large amount through. Sunglasses that block UV rays are vital to protect the eyes from the sun.
Eye doctors can test eyewear for ultraviolet protection.
The U.S. National Weather Service produces daily forecasts of UV levels based on the exposure levels in the table below. People with lighter skin need to be more cautious. People with darker skin may be able to tolerate more exposure. But even dark skin can burn. Apply SPF sunscreen Low 45 minutes Apply SPF sunscreen, wear a hat.