A new study found that ultraviolet rays can still harm your skin even after you move indoors. Learn the details, plus how to protect your skin

By Kelly Mickle
February 23, 2015
Corbis Images

Turns out, the sun may be even stronger than we thought: ultra-violet (UV) rays continue to damage our skin and increase our risk for cancer as long as four hours after we've moved indoors, new research from Yale University reveals.

While melanin, the pigment in skin cells, has long been believed to help shield skin from harmful UV rays, new findings suggest that the energy that does get absorbed may later be deposited into surrounding tissue, causing mutations in nearby DNA that can lead to cancer. While this is disheartening, the discovery could spur the development of "evening after" lotions that would help minimize the effect. In the meantime, dermatologists recommend wearing a sunscreen with a sun protection factor (SPF) of 15 or higher that offers broad-spectrum protection from both UVA and UVB rays. (And make sure you read the label carefully: Consumer Reports Says Some Sunscreen SPF Claims Are Inaccurate.)

Think you can skip the sunscreen routine until summer? Not so fast. Despite the cold, dark days of winter, your skin still needs protection. As much as 80 percent of the sun's UV rays still pass through the clouds, and you often get hit by these rays twice, as snow and ice reflect them back up to your skin-upping your risk for skin cancer and wrinkles too. Freezing temps also leave skin dry and irritated, making us more vulnerable to harsh UV light.

For year-round protection, slather on sunscreen at least 15 minutes before heading outdoors. Try our favorite picks from The Best Sun Protection Products of 2014 or the sun safety tips mentioned in Winter Beauty Tips from X-Games Stars.