Yeah, it does rain a bunch up here. Good news is it never gets really cold, but that is relative to what you are used to. As it rains so much, you don't get nearly as much slippery action when it first starts raining. Roads are ALWAYS washed clean and that probably makes rain riding much safer here than AZ.
Tracks nearby are Pacific Raceway about 45min south of Bellevue and Portland International in Portland, OR. Spokane has a track too. There are some excellent winding roads as you head up into the Cascades. I would expect simlar to what you would find in AZ mountains, but much greener.
Back to weather, we are currently enjoying what has to be a very dry October/November. I could ride every day for the past several weeks. It gets down to freezing occasionally, and you get plenty of frost, but rarely any snow or frozen streets. If you rode like it is cold out, you'd have little problem. We do get equal stretches of CRAP weather where it rains 80 days in a row some winters. I prefer a dryer, warmer climate, but Seattle CAN be really nice. If you want out of the heat, you would probably love the summers. Winters get sloppy most times.
Right now at 7:45 am, it is 35 degrees, clear and crisp with a beautiful sunrise showing off Mt Rainier--an excellent ride, too. I'd go riding today, but some bastard stole my CBR Sunday.