When I saw the thread title, my first thought was that I haven't finished preparing for summer season yet. Almost, but not finished.
Winter in the PNW is all about layers. And synthetic fabrics mostly. Mostly because I usually favor wearing a flannel shirt during the winter season. But I have a synthetic wicking layer under it. And usually fleece over that. Mostly I use capalene long johns, but a think Smartwool long john layer is pretty good as well. Nylon quick dry pants are my year around standby, covered with fleece pants over them in the winter.
I used to think that stocking foot waders just don't cut it for me in the winter, since I'm prone to cold feet and cold hands. The long term problem with insulated boot foot waders is that I start out warm and dry, but end up cold and wet or at least lukewarm and wet due to perspiration. My winter cure with breathable waders is to buy another set of wading boots a size larger than my usual summer ones. That way I can wear two heavy expedition weight merino wool socks inside my breathable waders. It doesn't keep me warm always, but cool and dry is a comfortable compromise.
And since I fish in the PNW in the winter, rain gear, always. I carry rain gear with me 365 days a year. It's a NW thing, and smart, too.