We may have rain here in Seattle, but if you can put up with a little wet we have nice bikeable weather all year round (in fact *crossed fingers* its been very dry on the weekends this winter). It usually doesn't get very cold here in the winter - and if it does get cold it is clear so no percipitation! It also does not usually get excessively hot or humid here in the summer. Our biggest downside is being so far north that our days in the winter are very very short - like sun up at close to 8am and dark at around 4:30 at the worst, of course that means light until about 10 pm in the summer though. The other bummer, the cost of living is quite high here - housing especially.

Otherwise it's great. Huge cycling community. Miles of bike trails if you can put up with the crowding and fairly sane drivers if you can't (at least compared to some of the stories I hear from other places). Traffic can be bad, but avoidable if you plan your living, working and commuting well. I rarely drive anywhere these days so its not my worry. Very green, very lush, little rain in the summer (shhh its a secret!). Relatively easy access to incredibly beautiful places like Mt. Rainier and Olympic National Park. Full compliment of cultural activites - oh and really great sushi.
I moved here from the east coast and I love it. I grew up in Pittsburgh and though I think its a really great city and undeserving of some of the bad reputation it retains from the old days of the steel mills, I sure don't miss the hot and humid summers and cold winters.