When exercising in cold weather, all of the following are good safety precautions except

-dress in layers to trap body heat
-skip sunscreen on sunny days to let the skin get warm
-wear snug clothing that will not stay damp
-wearing sunscreen of at least 15 spf



Answer :

-ski sunscreen on sunny days to let the skin get warm
You can not have the sunscreen on but you can get sun burnt 
-skip sunscreen on sunny day to let the skin get warm

why?

because sunscreen and warmth of skin are not correlated . . . (i.e. your skin isn't going to be warm just because you put sunscreen on - they have nothing to do with each other, much less with safety)