You will need SEVERAL. And all types of toppers in all sorts of weights. You can never have enough toppers living in the PNW. And weatherproof footwear.
You can wear a lightweight leather jacket in a Seattle Summer when we have an awful Summer. But we are having a beautiful and warm Summer this year!!!! So two piece dressing - nothing hot and sticky.
I suspect you will LOVE Portland weather for a while, Dana. Get your Fall and Winter dressing fix right away! Then you will probably miss wearing drapey linen knits and sandals. On the East Coast, the weather is as hot as it is cold - and you get to do both. In Seattle we live in Autumn and Spring weather a lot - which to me feels like Winter. I miss easy two piece dressing sans toppers, and I love wearing sleeveless tops sans layers. Just can't do it in Seattle. I run too cold.
I don't want to jinx our weather angels. We are having stunning weather now - warm but not hot - and two piece dressing has been a treat.
*un-jinxing*