I grew up in the Portland area. It's really beautiful but there are micro-climates and temperatures can vary. I lived close to the Columbia river gorge and the wind would howl. A wool pea jacket wouldn't keep me warm when walking as the wind would cut right through it. Leather works for dry days but I'm unsure about wet days. The northwest tech parkas made for rain & cold are workhorses.
But friends in other areas of Portland might live in shielded 'banana belt' regions and not get the brunt of wind and rain. Be prepared for a little bit of everything if you walk a lot