All you can do is live right, meditate, pray and hope for good luck.
Karma can do wonderful things.
Bottomline?
It's a crap shoot. I've had great weather, clear, somewhat windy 10-20 mph, and 50 degrees in November.
And then the next day it will blow 50MPH and hail.
Rain gear on, rain gear off. Freezing, then too hot.
Just book it and be prepared for everything. There are no guarantees in Oregon.