I understand!
With continuing weather anomalies blamed on 'global warming,' trying to pre-plan a trip based on
historical weather norms, or long range forecasts, is becoming increasingly difficult.

I just read that Chicago may break an 18 year snow record tomorrow.
Not a record of accumulated snowfall...but a record of 'snow less' days.

Well...hope you had a nice trip anyway. For your next Seattle trip, try for September.
I've always had great luck with Seattle weather around the autumnal equinox.