Earlier quoted context omitted.
You're probably well aware of this, but Vitamin D supplements have been life changing for me. There was an article a while back pleading to the FDA to fix the recommended daily limit, suggesting it might be 10x too low. I take 10,000 IU a day and the difference is very noticeable.
I get pretty significant SAD and 5000 IUs of Vitamin D helps a lot, but it's not enough for me. I'm planning to move to somewhere else in a year or two, maybe Seattle.
The May-August period has very few clouds and a not-too-hot sun, so that is a fine season from the point of view of spending time outdoors and letting your skin work for your body.