The sun works mysteriously: If you stand in front of it, feel its warm rays (especially at the height of summer). If you go in the shade, the beam heat is less. So you seem to be less at risk if you are not directly exposed to its rays, do you?
Wrong, says Carly Roman, a Seattle-based dermatologist. "Most people don't use sunscreen in winter because they think they are less likely to be exposed to sunlight," she explains to GQ. Roman points out that only one of the two types of ultraviolet rays, UVB, are less present during the winter. Ultraviolet A (UVA) rays are present throughout the winter.
To clarify:
UVA: Ultraviolet A rays are known as "long waves" and make up 95% of the rays affecting the Earth's surface. They can penetrate the skin much deeper than UVB rays and are responsible for signs of aging (dark spots and wrinkles). They also increase the chances of skin cancer. UVAs are more dangerous and can penetrate glass and clouds.
UVB: Ultraviolet B rays are known as "short waves" and do not penetrate the skin so deeply. They cause redness and sunburn. UVBs are most present from early spring to late autumn. They are less likely to penetrate glass like UVA. However, though they decrease during the winter, they can still reach the surface of the Earth.
Thus, UVA rays are also present during the cold season, even in the shade, even indoors. They even penetrate under clothes. So they are ubiquitous.
So the importance of using SPF cream all year long is understandable. Think of it like this: If you are now 30, after 30, would you like to look closer to 50 or 70? If you want to look younger, have healthy skin free of cancer, apply SPF daily.
