Alberta Cancer Foundation

You and UV

The UV index tells you how strong the sun’s rays are on any given day. Paying attention to these numbers can help you prevent sunburns, which are associated with an increased risk of skin cancer.

Here’s what the numbers mean:

Low (1-2)
Minimal protection required for normal activity. Wear sunglasses on bright days and beware of snow, which can nearly double UV strength.

Moderate (3-5)
Cover up, use sunscreen and a hat, particularly if you will be outside for 30 minutes or more. Take cover in the shade during midday.

High (6-7)
Protection is definitely required. Cover up, wear sunscreen and a hat, or you’ll get a burn. Reduce your time in the sun between 11 a.m. and 4 p.m. when the sun’s rays are the strongest.

Very High (8-10)
Take extra precautions because exposed skin will burn quickly. Avoid the sun between 11 a.m. and 4 p.m.

Extreme (11+)
Values of 11 or more are very rare in Canada, and are more common if you’re visiting the southern U.S. or the tropics. Unprotected skin can burn in minutes when the UV index is extreme. Watch out for white sand or other bright surfaces, which reflect the UV and make the chance of burning even greater.