Over the last 5 years, I've been in regular attendance at the Greenwood Car Show, which will be held this Saturday (June 28). It's one of my favorite summer events in Seattle. Walking the 1 mile stretch between 67th St. & 90th, while looking at incredible classic cars, trucks, and motorcycles is just a nice way to spend an afternoon in Seattle.
Weather.com currently indicates that the weather in Seattle on Saturday is going to be 69˚ with a 30% chance of rain. I know the 73% humidity will likely deter some folks from spending the day outside, but if you have any compulsion to check this out, I highly recommend it. It's good clean fun for the whole family.
Checkout some of last years cars here.