Not too many zero degree days, but I walked even when it was 15F out and snowing. I enjoy the cold and snow — I love me a brisk winter!
I might not walk as much in the rain, but cold and snow don’t bother me as long as I have good boots. This (and last) winter were pretty much ideal in my book. If I could somehow teleport NY to the Maine coast (cold winters, not above 80F in summer), I would.
The problem with San Diego isn’t climate, BTW. It’s lack of pedestrian and bicycle amenities. Walking or biking more than a mile from home often involves 4 or 6 lane streets with cars doing 50 mph. I’d probably walk if I lived in an older community near the coast, not so much if I lived inland. As I said, I could stand living in North Park, University Heights, Golden Hill, PB, OB and the like provided I worked nearby.
Not in some development where only exit is to a giant street with cars whizzing by and spewing exhaust. My test whether somewhere is worth living in is “can I live there 99% of the time without ever getting behind the wheel?” I like driving on road trips. I hate it for day-to-day use. Using a 2500 lb steel box or 400 lb motorcycle to haul a much lighter human around is an inelegant solution.