Why You Can Still Get A Sunburn When You're Indoors

We all know the typical drill — lather up on sunscreen when going outside to protect your skin from the sun, even when it's cloudy. But did you know your skin still needs protection indoors?

While it may sound unlikely, you could actually get a tan — or a sunburn — from sitting indoors by a window on a sunny day. Glass can effectively block out most ultraviolet (UV) rays, but not all of them. The difference lies between UVA and UVB rays. UVA rays can cause wrinkles, sunspots and other sun damage. The stronger UVB rays can directly damage the DNA in skin cells, causing sunburns and are linked to most skin cancers (via Keck Medicine).

Glass used in car, home, and office windows block out most UVB rays, but a smaller portion of UVA rays, according to the American Cancer Society. This means your skin still could see some sun damage if you are in direct sunlight.

Heightened sunburn risks and your daily commute

There are also other varying factors like UV index level, time of day — between 10 a.m. and 4 p.m. is usually the most intense UV ray time, and even your view. UV rays can bounce off surfaces like water, sand, and snow, causing higher chances of sunburn if your window faces any of these (via Healthline).

Sunburns can even occur while driving in the car. Most windshields protect against UVA and UVB rays, but side windows and rear windows often don't, according to Keck Medicine. That means you could be getting hours of sun exposure during your daily commute.

There are some benefits to getting some extra rays, though. Sitting in sunlight can be good for your mood and mental health, especially on a chilly winter day and vitamin D is made from UVB rays and you won't get enough of that unless you have direct sunlight exposure, according to Healthline.

Given all of these factors, it is wise to follow best practices and apply sunscreen daily, even if you don't plan on going outside or sitting by a window.