I've hit snow so many times , on every route; south from Vancouver; that when it comes time for tires , I'll be looking at traction tread.
No way out of Washington, Oregon , that doesn't have a pass with the possibility of snow, at that time of year , and I'm usually a week ahead of your departure date.
Hope the fires flanking I-5 are out by the time we travel.
From I-5, I've started going south of Bakersfield to avoid the traffic there , through Arvin, east of Arvin, on 223, there is a short steep climb to link to 58, but it's very light traffic, that route adds about 20 miles , but my best guess-timate would be a 45 min saving over all the traffic lights, through Bakersfield.
This year , I'll be going south from Kelowna, through Montana to visit friends who can no longer come south for health reasons, and the two times I've done the route there , I've hit snow. I-84 through Ontario OR, snow , 97 south to Weed CA, snow.
The one time I considered the coast route through OR. to miss the Passes on I-5 at the CA border, surf was running 38' and there was a tornado in Newport. We just travel at the wrong time of year for good dry weather.