Protection from sun exposure is important all year round, not just during the summer or at the pool. Any time the sun's ultraviolet (UV) rays are able to reach the earth, you need to protect yourself from excessive sun exposure. UV rays can cause skin damage during any season or temperature.
The hours between 10 a.m. and 4 p.m. during daylight savings time (9 a.m. - 3 p.m. during standard time) are usually the most hazardous for UV exposure in the continental United States. UV radiation is the greatest during the late spring and early summer in the Rocky Mountain Region.
UV rays reach you on cloudy and hazy days, as well as on bright and sunny days. UV rays will also reflect off any surface like water, cement, sand, and snow.