I'm south of you and only head as far north as SEATAC airport, which is why you never see me on the road. I'm one of those crazies
that rides all year long on my daily 50+ roundtrip commute (distance varies depending on what backroads I take to avoid traffic on the way home and also to try and eliminate the chicken strips on those curvy roads
).
The only thing that stops me is actual ice or snow on the road, although I've ridden home plenty of times where slush was on side streets or snow/hail was falling. I love those days when it's snowing on my ride because it looks so cool with the snow streaking by the faceshield and it gives you serious "tough guy" cred with the cage drivers.
A nice thing about the weather patterns here is that generally when it drops below freezing, the rain has stopped for a couple days and we've had sun to dry roads. My record cold commute was 17 degrees a few years ago. I would have beat that the next day, but had to take the kid to the dentist that morning which required driving the gas guzzling pickup.
This morning saw 34 degrees on the FJR temp readout as I headed out at 4:50am tucked in behind my Vstream barn door windshield while bundled in my Roadcrafter suit. The heated liner was plugged in and my hands were toasty in their heated gloves hiding behind the Vstrom handguards (wind guards actually). Not much hot-rodding going on due to cold roads and the fact that my PR2 rear tire is just below the wear bars (worn tire requires even more caution when the roads are wet).
On those days when conditions really are marginal due to ice or snow, I go into "Grandma" mode. This entails very gentle throttle application, very slow corners to keep the bike as upright as possible and cautious braking. Yea, it would be easier to take the truck but I like the challenge as long as it's not a suicide mission.