Clouds do not stop dangerous ultraviolet rays. And on sunny days, these harsh rays can reflect off concrete, water, snow and other surfaces. Like summer, winter rays are still the strongest during the middle of the day. (If your shadow is shorter than you are, the UV rays are very strong.)
So grab the sunscreen, a hat, a good pair of sunglasses (100 % UV protection) and lip balm with SPF protection when you're outside. SPF of 15 or higher is best. And have you skin checked regularly by your doctor.
Sun Protection Tips