If you're not in your swimsuit soaking up the rays on the beach, it can't be necessary to wear sunscreen, right? Wrong. Even when you're covered head-to-toe in winter gear with only your face uncovered, it's a good idea to slather some sunscreen on before you head out the door, and this is especially true when it's snowing. For one, snow on the ground reflects the sun's rays, making it possible to get a sunburn.
Also, many times on really sunny days in the summer, we know we need to reapply the sunscreen because our skin starts to feel warm. However, in the winter, you're less likely to feel, well, warm. So you could get a sunburn without even noticing it after spending just a few hours outside. The sun's rays are especially dangerous during winter sports like skiing or snowboarding because the high altitude puts you that much closer to the sun.
During the winter, purchase a face moisturizer that contains SPF for every day wear, or if you're heading up into the mountains, slather on a more robust sunscreen, like SPF 50. Lip balm with sun protection is also recommended.