Get lots of vitamin D. My wife used an S.A.D. light while in Law School and I think it helped a bit.
I don't know if I get any real Seasonal Affectedness, I just hate never seeing daylight. Couple that with cold weather and it's just....blah.
We usually do most of our mountain bike trail building during the winter months, so I get outside a fair amount.....and my goal is to do more snowboarding this year. Cost has usually been prohibitive ($100 minimum for a day)....well, not really so much prohibitive as fcking dumb and wasteful.
Heading on vacation at the end of this month, which is our first real winter vacation. Normally we go in the spring or fall. Be nice leaving cold and snow and being in green.
We're in a trap here. Good jobs, nice house, family, some friends....and most of all, no natural disasters. Ever.
Trade off is complete shut down for 6 months.