UVB rays are most intense at noon and the hours immediately before and after (between 10 a.m. and 3 p.m.), particularly in the late spring, summer, and early autumn. Although they are less concentrated at other times of the day and year, UVB and UVA can still damage the skin and eyes even in the dead of winter. UVA rays stay the same all day, every day, all year long. UVB rays also increase in intensity in relation to altitude and latitude. The higher the altitude, the greater the concentration of UVB rays. Likewise, the rays are more powerful the nearer the latitude to the equator. UV rays “bounce” off reflective surfaces, including water, sand, and snow. Thus, a skier, swimmer, fisherman, or beachcomber may be bombarded with UV rays from above and below. Many outdoors lovers who skipped sunscreen have learned this lesson the hard way.