The belief that cold weather protects skin from the sun is a misconception that can lead to significant damage. Tanning and sunburn are possible even in freezing temperatures, a fact often overlooked during winter outdoor activities. Tanning is a biological response where the skin produces pigment to shield itself from damage. This process depends entirely on invisible ultraviolet (UV) radiation, not the warmth of the air, and occurs regardless of the season.
The Role of UV Radiation, Not Temperature
The physical mechanism causing tanning is a photochemical reaction triggered by UV radiation, unrelated to the outside air temperature. The warmth associated with summer sun comes from infrared light, which is separate from the damaging UV wavelengths. Ultraviolet light includes UVA and UVB rays.
UVA rays penetrate deeply, contributing to aging and long-term damage, and their intensity remains constant throughout the year. UVB rays primarily cause sunburn; although slightly reduced in winter, they remain a threat. The skin produces melanin in response to both UVA and UVB exposure as a defensive measure, meaning the presence of sunlight makes tanning or burning possible, regardless of ambient temperature.
How Snow and Altitude Increase Sun Exposure
In cold, mountainous, and snowy regions, the risk of UV exposure can be significantly higher than during a summer day. This increased danger results from two combined environmental factors. Fresh snow is an efficient reflector of UV light, known as the albedo effect. Clean snow can reflect up to 80% of UV radiation, exposing the skin to the sun twice—once from above and again from below.
Higher elevations further compound the risk. For every 1,000 feet gained in altitude, UV exposure increases by 6% to 10% because the atmosphere is thinner and filters less radiation. This thinner air and reflective snow amplify UV intensity. Furthermore, the cooling effect of cold air masks the sun’s heat, leading individuals to underestimate how quickly their skin is being damaged.
Necessary Cold Weather Sun Protection
Protecting against intensified cold-weather sun requires a comprehensive approach for both skin and eyes. Broad-spectrum sunscreen with an SPF of 30 or higher is necessary for all exposed skin and should be reapplied regularly during extended outdoor periods. Apply sunscreen under the chin, nostrils, and ears, as these areas are susceptible to reflected UV rays bouncing off the snow.
Wearing protective layers, including hats, gloves, and neck gaiters, shields the skin from direct and reflected light. Eye protection is essential to prevent photokeratitis, or snow blindness, which is a sunburn of the cornea. Use goggles or sunglasses that block 100% of both UVA and UVB radiation to mitigate the risk of reflected light causing eye damage.