xmACIS is easily the best resource now.
https://xmacis.rcc-acis.org/
Also has most Canadian stations available on it if you search, though there are some holes and unfortunately the major airport data for stations like YJJ only goes through 2013.
Lots of tools on there still though. Here's Shawnigan Lake's daily record maximums as an example from 1913 up through the station's end in 2023:
My point has been about the PNW overall, and how in this case, your little corner doesn't represent the PNW overall. 2015 was far different for most of the PNW. The SEA stats are much more representative for the region. It is what it is.
Is that really so "mind boggling"?