Sure, Sequim gets all the press for having 300 days of sunshine and only 18 inches of rain per year, thanks to the Olympic Rain Shadow but sometimes they lend it out to other regions.
Case in point, Sunday's big cold front that drenched some areas with as much as 1 inch of rain or more -- and left others with their rain gauge barely wet.
Take a look at this map of the 24-hour rainfall totals, courtesy of the CoCoRahs volunteer rainfall network:
Yes, that's 1.10"-1.80" of rain in Mason County, about 1" in Thurston County, then 0.75-1.00" in Pierce County, about 0.50"-0.75" in southern King County, dropping to about 0.25" in northern King County, to barely 0.10" in Snohomish County... and barely measurable on Whidbey Island and the Port Townsend area. Just plucking two cities on there finds that Everett got about 0.05" while Tacoma had 0.99" -- about 60 miles apart.
That's due to the southwest winds blasting into the Olympic Mountains -- creating extra rain on the windward side, but as the air sinks down the leeward side, the air dries out quite a bit. This particular storm's wind had a little more westerly component to it than usual that shifted the heart of the rain shadow further east from Sequim to centering it around Whidbey Island -- although Sequim got the edge of the shadow and only reported about 0.12" which was much less than the half inch of rain that fell in nearby Port Angeles.
But it just shows off our wide range of microclimate around here and how much influence the Olympic Mountains play in our weather.