Most people want to ease up on sun protection during winter as the sun feels weaker and they assume they are less likely to burn. Sadly only one of the two UV perpetrators, UVB, is actually reduced by clouds. And while these UVB rays are the culprit behind sunburn, the other type of UV rays, UVA, are very much present year round- and it’s imperative to avoid them.
Before we dive any deeper, here’s a quick refresher on UVA and UVB rays.
UVA Rays– Ultraviolet A Rays, also known as ‘long wave’ rays make up 95% of the rays that reach the surface of earth. They can penetrate the skin much deeper than UVB rays and are responsible for signs of ageing- think dark spots, wrinkles. They can also initiate skin cancer. UVA rays can penetrate glass and clouds.
UVB Rays– Ultraviolet B rays or ‘shortwave’ rays, don’t penetrate the skin as deeply. They’re what causes redness and sunburns. They are most intense during the day’s sunniest hours. They are not as likely to penetrate glass as UVA rays. Even though they dwindle in winter, many reach the earth’s surface and are easily reflected off snow and ice. This makes them a bigger threat on the the ski slopes and at higher altitude.
In summary, these photo-aging UVA rays can find you year round- even in winter, even in rain, even in the shade, and even indoors! UVA rays are basically omnipresent- even in small amounts.
Sun protection is honestly simple. When there is sun, you protect yourself. In the absence of daylight there aren’t many UV rays being hurled your way. That’s why you can skip the sunscreen when you go out at night. But even in winter when the days are short and the sun hides behind the clouds, UV rays are beaming down ready to hit your skin.
The UV index on the weather app on iphones and most android phones is a useful guide to determine what degree of sun protection should be adhered to on any given day- no matter what the season.
Take home message- sunscreen every day no matter what the season, if the UV index in your area is 3 or above it is best to take extra precautions.