The UV Index is a simple measure of the intensity of the sun's ultraviolet (UV) rays, using a scale that runs from 0 (lowest intensity) to 12 (highest).
UV rays are a form of invisible, high-energy light. UV rays have shorter wavelengths than visible light.
Because the sun's UV rays can damage your eyes and skin. The UV Index tells you when to be careful. Sunburn is the immediate result of too much exposure to UV rays, but skin cancers and cataracts can develop many decades later as a result of excessive exposure earlier in life. Since most of our exposure to sunlight occurs during childhood and adolescence, proper precautions in these years can prevent serious health problems later on.
Every day especially from May to September. The sun's UV rays are stronger on some days than on others. These variations are due to things like seasonal changes in the angle of incoming sunlight, daily changes in the ozone layer, and cloudiness.
With your daily weather forecast - on radio and TV, in your paper or at this website.
It's easy. The higher the index, the more careful you have to be.
UV isn't usually a problem. But be careful when it's bright and there's snow on the ground. UV rays bounce back from the snow. Special UV sunglasses will help to protect your eyes.
Take care. Some people get sunburned in about 30 minutes. Wear big hats and clothes that cover yourskin. Put sunscreen on skin that you can't cover. Don't be fooled if it's cool or slightly cloudy. The UV still gets through.
Look out! Some people get sunburned in only 15 minutes. Don't stay too long in the sun, especially between 11 a.m. and 4 p.m. Wear your sunglasses (the special UV ones) and stay in the shade. Put on more sunscreen every 2 hours or after swimming or working up a good sweat. Be especially careful when you're down south on winter holidays. On clear, sunny days in the tropics, the UV Index is normally between 11 and 14.
The Green LaneTM,
Environment Canada's World Wide Web Site.