I live in Southern CA so eat your hearts out. Hehe heh.

But I'm in a lab all day. So I take large doses of d3 especially when one of the zombies at work starts sniffing and coughing. For every one time I get sick they get sick 20 times! Some of them are sick more days than they are well.

The sun is just too far away in the winter in the northern climates for you to get any appreciable amount of vitamin D. If you're out skiing all day or playing in the snow, where the sun reflects off the snow and you don't wear sun screen you might make a little bit of vitamin D. But with very little skin exposure it probably won't be much. This is why our grandmothers insisted on our parents taking cod liver oil during the winter. They knew it was good for you.

If you get your serum D3 levels boosted high enough, summer exposure will be enough and low levels of supplementation (1,000iu-5,000iu) will be enough to get you thru fall and winter.

For up to date information on vitamin d research: http://www.vitamindcouncil.org