But I bet you can't guess the least-sunny place in the U.S.
With just 48 sunny days a year, it's Elkins, West Virginia, just edging out Astoria, Oregon which has 50.
As for the rest of Seattle's days, we average 226 cloudy days (4th most in the U.S.) and 81 partly cloudy days. Of all those days, we get 155 days of rain a year (we've had 97 so far this year.)
Incidentally, Seattle is on pace this year -- having just under 40 sunny days so far this year.