Well, this year's been a bit odd.
Which Seattle do you live in? It's been fall for more than a week now, and sunny. Well, until today. Now it's so gray, overcast and nipply, you can't see your own shadow, like it will be until next August.
I bicycled to work today in the sunshine this morning, I swear!
We've had a fairly mild summer (I think we only had two or three days in the 90's) and it's been unseasonably warm for the most part (it's still upper 70's today, although it's looking like low 60's/high 50's over the weekend).
Generally though, around late Sept is when the weather starts to go crappy and the shitstorm is in full swing by mid Oct (Trick or Treating with the kids when it's freezing cold and raining is a LOT fun...NOT!).
But you're right, lately it's been pretty nice. I think however, our great weather is numbered.