Sunburns that continue to worsen several days after exposure may be a sun allergy. Overexposure to sunlight causes premature aging of the skin. But all of these problems can be thought of as preparation for later episodes of skin cancer. The danger of ultraviolet radiation is increased by reflection. Depending on the angle of reflection, water can reflect up to 100 percent of UV light.
Angle of reflection is determined by the height of the sun above the horizon.
Early in the morning and late in the evening, with the sun low in the sky, water may bounce only 10 percent of the UV rays back at you. At noon, with the sun directly overhead, water absorbs most ultraviolet light, and reflectivity drops to about five percent. Sun-related skin problems, happily, are among the most preventable of outdoor problems. Take cover . . . Tight-weave clothing blocks a large amount of UV radiation, especially if it stays reasonably dry.