If you're determined to get that bronzed tan, a cloudy day doesn't have to ruin your plans. In fact, 87 percent of the sun's rays penetrate clouds, fog or mist, according to the Georgia Emergency Medical Services for Children. Ultraviolet (UV) radiation -- the rays from the sun that give you tans and sunburns, both of which are a sign of skin damage -- isn't visible to the human eye. After spending time outside, however, you'll be able to see the effect of the UV rays on your skin.
Decide whether the health risks are worth the appearance of a tan. Sun exposure increases your risk for skin cancer, premature aging and eye damage, and there is no such thing as a safe tan.
Wear sunglasses that provide 100 percent UVA and UVB protection to protect your eyes from UV radiation. Don't assume that dark lenses automatically protect your eyes; the darkness of the lens isn't related to its UV-protection ability.
Apply broad-spectrum sunscreen with a SPF of at least 15 to all areas of exposed skin. You'll tan more slowly, but you'll also avoid sunburns. Reapply every two hours.
Wait up to 48 hours for your tan to develop. Your skin continues to produce melanin in an attempt to protect itself for up to two days after exposure to UV rays, so your tan won't show immediately.