You don’t regularly apply sunscreen
Sunscreen is important year-round, even in the wintertime on the cloudiest or snowiest of days. ‘While UVB rays decline in intensity during the winter months, UVA rays do not, and these are the ones responsible for most of the DNA damage that leads to skin cancer and premature aging,’ warns Dr. Lain. For this reason, he recommends that all his patients wear a broad-spectrum sunscreen with at least an SPF 30 year-round.