Yes… but no. Allow me to explain before you start rearranging your furniture near a sunny window. You absolutely can get a tan through glass, but only half of the tanning equation works.
Remember high school science? The sun emits mainly two types of UV rays that mess with your skin: UVA and UVB. Think of them as the aggressive big brother (UVA) and the responsible, bossy older sister (UVB). Glass is like a very strict bouncer for UVB rays.
Standard window glass blocks nearly 100% of UVB rays. Why does that matter? Because UVB is the ray that causes sunburn and triggers your body to produce melanin—the actual tanning pigment. So, you're not getting that deep, lasting tan from a car ride.
Enter the Sneaky Villain: UVA
Here’s where it gets tricky. Glass is terrible at blocking UVA rays. About 75% of UVA rays pass right through like they own the place. And guess what? UVA rays do cause skin darkening—but it’s a cheap, temporary tan.
You know that instant, “I’m glowing” look you get after sitting in a sunny car for an hour? That’s UVA oxidizing the melanin you already have. It’s like fake tan that lasts a day, but with the added bonus of deep wrinkles and DNA damage.
So, you can get a tan through glass—but it’s the shady, unhealthy cousin of a real tan. It’s the “I look a bit darker but in a sickly, leathery way” kind of tan. Not the Cancún glow you were hoping for.
