UV Radiation Poses Hidden Risk for Skiers - Vital Signs - NYTimes.com
Scientists studying sun safety took multiple readings of ultraviolet radiation at 32 high-altitude ski areas in western North America and interviewed thousands of skiers to find out whether they took precautions against the sun, like wearing hats, sunscreen and goggles, at appropriate times. Their conclusion was: only occasionally.
"There were lots of findings, but the big takeaway is that people do not know when UV is high and do not take precautions," said Peter A. Andersen, a professor of health communications at San Diego State University. "People took precautions not only when it was sunny but when it was warmer, and that's an erroneous calculation in people's minds. There is absolutely no correlation between temperature and UV radiation."
There can also be a lot of exposure to UV radiation on cloudy days, he said.