I live up North (capital N) from you, where we have ~4 months of calcium spread on our roads to manage the accumulating ice every winter. A well-maintained car has the chance to live long enough to succumb to rust from that.
Rustproofing is still a good treatment to get done to delay and minimize damage, but it's a thorough and slightly expensive job.
People who have a hobby car usually retire it in a garage from November to April-May instead.