People can tan on a cloudy day; in fact, they can even get a sunburn. Clouds let through the sun's UVA and UVB rays, which tan and burn the skin. In fact, clouds usually block only about one-fifth of the sun's rays, according to Do Something.
Though many people think a tan looks nice, it is a visible sign that the sun is damaging the skin. Skin damage over time leads to an increased risk for skin cancer, according to WebMD. To protect the skin, people should use sunscreen that offers a broad spectrum protection, as well as wearing long-sleeved clothing to help block out the sun's rays.