I spent a year and a half up there on a temp job assignment 6 months ago. As people have said above, expect gloomy/overcast/light rain type weather for the majority of the year (7-9) months and it can be especially brutal in the winter since it is located at such a high latitude and the sun will be gone by 4pm. Summer time weather is unbeatable though, mid 70s low 80s, clear skies, no smog, and daylight until 10 pm. If you like to snowboard/ski, there is some great resorts like an hr and a half away.
I lived in kirkland which is just north of redmond. The redmond/bellevue area is very nice and probably the most expensive place to live outside of the nice skyrises in downtown Seattle, reminded me of orange county where I am from. They have great parks up there, check out mary moor especially if you have a dog since the dog park there is pretty awesome. Traffic can be brutal in the the redmond area during rush hour, so try to live as close to work as possible. My wife's commute from kirkland to redmond in the mornings took 30+ minutes (8 miles), while my commute from kirkland to everett (going north and 25 miles) took 25 minutes.
People also tend to drive slower, 70 mph or so in the fast lane.