Clouds don't block UV rays.

Yes. Up to 80% of UV radiation penetrates cloud cover, and if you’re spending more than 15 minutes outside, you’re still getting exposure. You just don’t feel it as much because it’s cooler and less bright.

Clouds block visible light, not ultraviolet. That’s a different part of the spectrum. So you can absolutely burn on an overcast day — I’ve done it, and it’s a confusing way to learn this lesson.

If you’re going for a walk, running errands, or sitting on a patio, throw on SPF 30. It’s not a sunbathing day, but your skin won’t know the difference.

Your future dermatologist is on your side here.