You made me curious, so here's a list of US cities with more average rainy/snowy days per year than Seattle[1]:
223: Juneau, Alaska
209: Mt. Washington, N.H.
169: Buffalo, N.Y.
163: Olympia, Wash.
161: Caribou, Maine
155 (tied, interestingly): Cleveland, Ohio
155: Seattle-Tacoma, Wash.
At 37 inches of rain per year, it's not a particularly high
volume of rain; it's just spread out over a lot of days. San Francisco is down at 63 rainy days and 20 inches per year, for comparison.
[1] http://www.infoplease.com/ipa/A0762183.html