Samatr,
Seattle has the most bi polar weather on earth in the spring. The rain can come at any time, and some come right after it. It doesn't rain hard, you get 10 minutes of sprinkles, then the sunshine, then some more rain, and then the rest of the day it'll be lovely, and out of no where you get thunder and lightning.
But we have the best summers you can imagine. Not too hot, no humidity, it's beautiful. Seattle in July and August is hard to beat.