For what it is worth, I have a friend in Missouri who has had a 1940's model GE out on the screened porch for years and it works great in Winter and Summer. Missouri winters get down in the teens, but seldom below 10 degrees. Summers hang in the 90's for weeks and some times over 100.
Again, this "iceBox" was built in the 40's and they just don't build them like they used to. It'll even freeze beer in the summer if it is on the top shelf next to the mini freezer compartment. What a great refrigerator it is!!
p.s. I have lots of friends in Missouri with fridges in their garages with no problems. Convenience is the issue here - avoid the stairs unless you entertain down there.
p.s.s. I'm not a fridge technician, but I like my beer cold!!!