November Sun: The Most Underestimated UV of the Year
Cold and gray doesn't mean safe.
Up to about 80% of UV rays penetrate clouds, and UVA stays relatively constant year-round, so a cold, overcast November day can still deliver skin-damaging UV.
Dermatologists warn that cool, gray weather creates a false sense of safety: clouds let most UV through, and the deeper-penetrating UVA that ages skin barely changes with the seasons.
Questions we get a lot
Is sunscreen necessary on cloudy days?
Yes. Up to 80% of UV rays pass through clouds, and UVA — the deeper-penetrating, aging wavelength — stays fairly constant regardless of cloud cover. A cool, overcast day can still deliver enough UV to damage skin, so daily broad-spectrum sunscreen is recommended.
Do I really need sunscreen in November and through the winter?
Yes. While UVB and the UV Index dip in winter, UVA stays relatively steady and still drives aging and DNA damage. Cold, gray weather doesn't block it, and time near windows adds up. A daily broad-spectrum SPF on exposed skin keeps protection consistent year-round.
Does UV come through windows on a gray winter day?
Yes. Standard glass blocks most UVB but lets UVA through, so sitting by a window at home, in the office, or in a car still exposes skin to aging rays — even in November when it's overcast. If you spend the day near windows, daily sunscreen on your face and hands is still worthwhile.
r/SkincareAddiction: 'Do I really need sunscreen in the dead of winter when it's cloudy every day?'
