Personal preference in your case since you don't have real winter. When I lived in Ohio it was pretty much a must to swap my summer only tires and 18" wheels for all seasons or snow tires for winter. The main reason was safety, but also the salt, snow, ice, potholes, and junk isn't kind to wheels...or anything metal for that matter haha.

I would say that if all you are going to get is rain and fog, I wouldn't personally swap, but sure if you want to, go for it.