What about light therapy in addition to getting out as much as you can in the inclement weather? Also, are you supplementing Vitamin D/have you had your Vitamin D levels checked?
I live in CA now, but I did 11 years in Seattle, so I can definitely relate. I definitely had to get outside (no matter how bundled up) on every day with some sun, even if it was just walking a few blocks to the store, being outside was restorative. And it was my doc in Seattle who first turned me on to Vitamin D supplementation - after she'd seen legions of patients who were chronically deficient.