One of my beautiful nieces asked me if she needed to wear sunscreen every day. “Even when the sun isn’t shining,” she asked?


She’s not the first to ask, so I thought in a month when the sun isn’t shining every day and it’s rainy or snowy outside, there might be merit in talking some truth about the sun and UV radiation.

Ready? Let’s geek out.

The sun emits three kinds of UV light: long-wavelength UVA, medium-wavelength UVB and short-wavelength UVC. The shorter the wavelength, the stronger the light. The good news is that the strongest, most deadly UVC radiation is absorbed by our atmosphere and never reaches the earth. If it did, it has the strength to kill us instantly. Yikes!

The longer rays do penetrate the atmosphere and can cause damage to our skin. The UVB rays are known as the Burning Rays. These are the ones that are strongest between 10am and 2pm during the summer months. That’s when the sun is hitting the earth more directly. They can cause visible sunburns and skin cancer (most commonly the nonmelanoma types originating in the epidermis).

UVA rays are known as the Aging Rays. They are the long rays that penetrate deep into the dermis, can destroy collagen and elastin (causing wrinkles and sagging) and can also cause the release of brown melanin resulting in “liver spots.” UVA rays can also mutate your DNA, which can lead to skin cancer.

Unlike UVB rays which are present on sunny days and can cause a painful and visible sunburn, UVA rays strike the earth and your skin from sunup to sundown, rain or shine, all year long. They are equally as strong in the morning as they are at noon or dinner time and can penetrate glass, some plastics, and clothing. And, 80% of the sun’s rays penetrate clouds.


Yes, and that’s why you need to wear sunscreen every day, rain or shine.

But there’s more. As the ozone layer gets thinner, penetration by all wavelengths increases, resulting in earlier and more aggressive skin damage. So, while it used to be okay to go without sunscreen if you were only spending a few minutes a day in the sun or even longer when the sun wasn’t shining or you were indoors, that’s not the case anymore.

Now, it’s important to wear a sunscreen every day; one that protects you from UVB and UVA rays. Sunscreen technologies have advanced significantly since the late 1970s and now most provide protection from both harmful UV rays. When it’s applied correctly, SPF 15 blocks 93% of UVB rays, SPF 30 blocks 97% of UVB rays, and SPF 50 blocks 99% of UVB rays.

So, my sweet niece (and all my other friends and family), please protect the biggest organ on your body—your skin—with the best sunscreen you can find. And, use it every day whether sitting in a sunny office, commuting on the freeway, or walking the dog. Your skin will thank you.