First of all, you can check out the monthly UV averages here (for my local readers in North Bay we're closest in latitude to Vancouver) to get an accurate picture of what month we need to start worrying about the sun. That said, snow can reflect a significant percentage of UV rays, so we need to be careful in the winter too:
But you can find out the UV value each day through Environment Canada here:http://www.ec.gc.ca/uv/default.asp?lang=En&n=396B9A58-1
In general, it's important to strike a balance between:
1) healthy sun exposure
2) covering up
3) applying sunscreen
Basically, you need some unprotected sun exposure in order to stay healthy (this allows your body to produce and store vitamin D). In my research, one source said the required sun exposure was as little as ten minutes twice a week, but this is probably a bit on the low side. If you want to get a good sense for how much exposure to aim for, check out this calculator the Norwegians produced, it's pretty cool! http://nadir.nilu.no/~olaeng/fastrt/VitD-ez_quartMED.html (this is a handy little how-to guide http://www.self.com/fooddiet/blogs/nutritiondata/2010/07/how-much-sunshine-do-you-need.html)
Then, it's time to reach for the sunscreen, right? Well.......you do realize that you're slathering chemicals all over your skin? If you can cover up, why not do that instead? If you can't cover up (you're in the wind, you're playing beach volleyball, you're swimming, etc.) then consider choosing a sunscreen that contains a 'physical block' of the sun. This means the sunscreen actually gets in the way of the rays of the sun, generally through 'zinc oxide' or 'titanium dioxide.' This is preferable because you aren't absorbing chemicals meant to minimize the harmful effects of the sun. However, be warned that the physical block sunscreens can leave a white residue on the skin.
These blockers are frequently found in childrens' sunscreens. I've tried a number of the healthier sunscreens and my favourite product is this: http://www.caribbean-sol.com/SPF-25-Biodegradable-Sunscreen---6oz- (SPF 25, titanium dioxide 9%) and my least favourite is this http://www.heiko.ca/ (SPF 30, titanium dioxide 14%) just because it left more of a white residue than I could handle (though I will concede it is difficult to wash off!). Generally, I save my more conventional sunscreens for when I'm wearing fancier clothes but still want sun protection. You can check out the details of a fair number of sunscreens here:
Overwhelmed? Just adhere to the following:
1) don't be afraid of minimal sun exposure
2) try to cover up whenever you can
3) if you do need to expose your skin, aim for a sunscreen that works primarily through the physical sun blockers 'titanium dioxide' and 'zinc oxide'
4) if you need to, use a conventional/chemical sunscreen
and, if you can
5) check the daily UV with Environment Canada before you head out the door!