When is the best time to see the Pacific Northwest?

North of Seattle about 60-70 miles on I-5, is the Skagit Tulip Festival. World famous tulips grow in color-carpeted fields as far as the eye can see. It's really a beautiful sight. Here's the link to the websitea href="http://www.tulipfestival.org/" rel="nofollow"http://www.tulipfestival.org//a