5 Things to Know About Sunscreen Near Windows

Reapply every two hours if you’re within arm’s reach of a window getting direct sunlight. Windows block most UVB rays but let through UVA rays, which age skin and raise cancer risk.

Sitting next to a south-facing window for three hours means real UV exposure. UVA accumulates even if you don’t burn, so treat it like being outdoors.

If the window has UV-blocking film or you’re more than a few feet away, stretch to every 3–4 hours. Distance and film reduce exposure significantly.

On cloudy days or with tinted glass, one application in the morning is usually enough. But if you’re paranoid about skin damage, reapply at lunch.

It’s better to oversunscreen than to realize too late. UVA damage is cumulative and invisible until it’s not.