Michigan here and, for the most part, I have driven all my vettes all year long. The '78 was the worse in winter. Gave it away at 180,000 miles to get the '87. The '87 was OK all year long, but now is resting with 200,000+ miles on her. Not sure what to do with the '87. Either put some TLC and $$ into it, try to sell it or maybe even donate to the local school for a project car in their work shop. I now drive (year round)a 2006 with no complaints. I do however refrain if it is snowing or just really bad on the roads. Then I use the 4x4 pickup truck. I like to refer to my vette as my "economical" vehicle since the gas mileage is AT LEAST twice as good as the truck.
Dave

I also had a '73 back in the day. At that time I lived in Denver. Drove it in the snow all the time.

the ZR1 stayed in the garage and the C6 Mallette stays put, although it sees alot more driving time than the Z did. all the rest of them saw year round driving and the 88 convertable was driven 40 miles one way to work. loved driving them.