Good article about the need for winter sunscreen:
https://www.cosmeticscop.com/BULLETIN/010809-full.htm?utm_source=Beauty_Bulletin&utm_medium=Email&utm_content=BBProduct_review1&utm_campaign=010809_BeautyBulletin&emc=el&m=288276&l=14&v=8674a1dc02#review1
Winter in many parts of the United States and northern regions of Canada means cold, windy, snowy weather without much sunlight to offset the chill. You’re likely spending much more time indoors and less time outdoors, not to mention wearing more clothing to stay warm. With less time spent outside and a minimal amount of exposed skin, you may have abandoned daily use of sunscreen. After all, if you’re rarely outside and you’re all bundled up when you do venture out, what’s the point, right? Wrong! Although the sun may not be shining and the hours of daylight are fewer than during spring and summer, abandoning your daily sunscreen habit would be a skin care (meaning antiwrinkle) mistake. Here’s why:
Even when you’re clothed in layers to defend against the cold, chances are good that a portion of your face, if not all of it, is still exposed. That means damage is still taking place if you didn’t apply sunscreen. Whether it’s the middle of January or you’re heading to the beach in June, you need sunscreen 365 days a year. Of course, in the summer months and in climates that are sunny year-round you have almost daily reminders as to why you should protect your skin from UV damage. But what you must remember when clouds prevail or the weather turns cold and gray are three basic facts about UV damage:
1. Sun damage is about your skin seeing daylight not just “sunshine”.
2. Sun damage begins within the first minute of unprotected exposure.
3. The bad rays of the sun penetrate windows
I know winter weather can be deceptive to say the least, because without question your skin is not being exposed to the same intense radiation you’ll get in summer or sunny climates. However, even though you cannot feel the sun warming your skin (and may not even be able to see it through the thick cloud cover that’s overstayed its welcome) ultraviolet light is still present and still capable of harming your skin. Ignoring sunscreen during winter months just doesn’t make sense, especially if part of your skin care concern is about preventing or reducing wrinkles.
Still not convinced? Let me add a few more facts that may be of help. You may not know that the sun’s aging UV rays are no match for cloud cover. Clouds offer some UV protection, but enough skin-damaging rays break right through dreary winter clouds that damage will still occur. It’s also critical to keep in mind that snow is an excellent UV light reflector. So depending on where you live or where you are vacationing not only are UVA rays bombarding your skin from above, but they’re bouncing off the glaring white snow and hitting you from below, too. And for all of you skiers out there, don’t forget that altitude is also a sun enhancer. For every 1,000-foot increase in altitude the ultraviolet radiation potency increases by 4%. To make matters worse, increased elevations are even more damaging for unprotected skin. That’s because the UV protection from the ozone layer of the atmosphere is typically thinner during winter months, so additional UV light to reach your skin. (Source:
https://www.telemedicine.org/sundam/sundam2.4.2.html).
If you’re spending little time outdoors and getting through the typical cold, gray winter months inside a toasty, heated room, you may want to change the sunscreen you use. For example, it may make good sense for you to apply a sunscreen rated SPF 30 or greater during summer months or in sunny climates; however, a high SPF rating becomes extraneous when you’re spending most of your daylight hours indoors and the sun isn’t shining; there just isn’t that much time for significant UV light exposure. Of course I’m not implying you should skip sunscreen (no way!), but you’ll likely be just fine applying one rated SPF 15. Regardless of whether you choose to decrease your SPF protection or not, you would never want to go lower than using a sunscreen rated SPF 15. Also, you still have to make sure to apply sunscreen liberally and only use one that contains one or more of the active ingredients that ensures sufficient UVA protection: titanium dioxide, zinc oxide, avobenzone (sometimes listed as butyl methoxydibenzoylmethane), ecamsule (Mexoryl SX) or Tinosorb.