May number of 80+ days at PDX. The 10 year average is now about double what it was 1950-2010. We have seen a number of years like 2015, 2016, 2018, 2021, and 2023 where summer effectively began in May. Whereas that was maybe a once a decade phenomenon pre-2015.
The median temperature in midwinter isn't really that different between the Willamette Valley and the Sacramento Valley given the latitude difference - this is when the N/S gradient is generally at its lowest. The extrema, however, are very different - the cold snaps in the PNW are much more severe (Dec 2013 in Eugene is impossible anywhere in lowland CA) and the warm end potential is usually much higher down south due to more downsloping and lower latitude.