When the forecast shows highs in the 20s with a blizzard on the way, it’s second nature to suit up with a heavy coat, hat, scarf, and gloves. But even when bundled to the gills, here’s one more step to take before braving the tundra: apply sunscreen. Regardless of the temperature or time of year, the sun emits ultraviolet (UV) rays, a type of invisible radiation that can harm our skin and lead to premature aging or skin cancer. The best defense against the damaging effects of UV rays? Slather on sunscreen like it’s July.

Hazy Shade of Winter — Why It Matters

winter sun While summer is considered the high season for UV rays, the rays are still quite strong in winter, and certain winter-related factors can even increase their strength. Snow can reflect up to 80 percent of UV rays, and for those snow-sport lovers (think skiing, snowboarding, or hiking) altitude can also increase UV strength by 10 to 12 percent. One study found that skiers at an altitude of 2km were exposed to UV rays 20 to 30 percent greater than at a lower altitude site Enhanced UV exposure on a ski-field compared with exposures at sea level. Allen, M, McKenzie, R. Department of Electrical and Computer Engineering, University of Canterbury. Photobiological and photochemical sciences: Official journal of the European Photochemistry Association and the European Society for Photobiology, 2005 May;4(5):429-37.. Another study showed people who participate in alpine sports are at a greater risk for squamous cell carcinoma, a type of skin cancer Outdoor sports and skin cancer. Moehrle, M. Department of Dermatology, University Hospital Tuebingen, Liebermeisterstr, Germany. Clinics in Dermatology, 2008 Jan-Feb;26(1):12-5.. Just protect that skin, people— goggle burns just aren’t sexy, even on Kim Kardashian.

But it doesn’t have to be snowy for UV rays to cause skin damage. Even on a cloudy winter day, up to 80 percent of UV rays reach the ground, so for those not shredding the slopes, skin is still at risk and should be protected Environmental cues to UV radiation and personal sun protection in outdoor winter recreation. Anderson, PA, Buller, DB, Walkosz, BJ, et al. School of Communication, San Diego State University. Archives of Dermatology, 2010 Nov;146(11):1241-7..

Cloudy with a Chance of UV Damage – The Answer/Debate

It’s widely agreed that sunscreen should be worn basically any time the skin is exposed outdoors— regardless of the forecast. Research shows both types of UV rays, UV-A and UV-B, can cause skin cancer, so a broad spectrum sunscreen with an SPF above 15 is recommended to protect against both. Some research suggests skiers should use at least an SPF 30, so anyone who spends a lot of time outside in snowy climates should consider upping the SPF as well Ultraviolet radiation in alpine skiing: magnitude of exposure and importance of regular protection. Rigel, EG, Lebwohl, MG, Rigel, AC, et al. Riverdale Country School, New York, NY. Archives of Dermatology, 2003 Jan;139(1):60-2. Broad-spectrum sunscreens provide better protection from solar ultraviolet-simulated radiation and natural sunlight-induced immunosuppression in human beings. Moyal, DD, Fourtanier, AM. L'Oréal Recherche, Clichy, France. Journal of the American Academy of Dermatology, 2008 May;58(5 Suppl 2):S149-54.. Both SPF level and broad-spectrum status can be found right on the label of any sunscreen, and the FDA is in the process of regulating these labels (hopefully within the next six months).

Regardless, sunscreen should be reapplied at least every two hours, and sooner if sweating or swimming. It’s also helpful to check the local UV index each day (just like the weather report) to see how strong the sun’s rays will be. Special bonus: That coconut-y scent of many sunscreens can conjure up daydreams of tropical vacations, even when the weather outside is frightful!

What's your SPF of choice?

The Takeaway

Yes, no matter the weather, the best bet is to slather on that sunscreen like it's the middle of summer!