I would very much consider immigration to western Ireland, Scotland, or the Netherlands if I hadn't built a life for myself in Northern California. As of now, the only reasonably affordable (not actually affordable) areas to live in with a temperate climates are in parts of Sonoma and Humbolt Counties, and Salinas.
Any serious move would take some convincing, especially with a partner who is from the area. As someone who prefers the cool fog to warm sun, there aren't a lot of friendly climate zones friendly that don't involve the pacific northwest, but that's a tough sell to normal folks that think grey skies are unpleasant.
As someone pretty much fatalistic about stopping climate change, I think the fortunes may favor the pacific northwest over Northern Europe in the next 50 years. It's an awkward gamble to make, but it's one that takes a lot more than just weather into account.
I do, but when moving here it was just my wife (then gf) and I on working holiday visas. Ireland is wonderful in many respects but also a deeply frustrating place, it's extremely car-dependent outside the middle of Dublin and perhaps what's harder is that most people see that as fine. Climate breakdown is viewed as a far away problem for other people, and rural communities can be insular. I have heard that some areas in Clare and West Cork are transforming, though.
That being said, I live in a beautiful house on 3.5 acres a 15 minute bike ride from the train station and we want to move to the Netherlands so our kids can have actual freedom before learning to drive. Also a lot more jobs on climatebase.org are in NL (and DE), they're never in Ireland.