Our chese/lab mix lived most of her life outdoors at our homes in Grand Portage then Hovland, inland from Lake Superior. We picked her up at Hollow Rock Resort from the old owners when she was a year old and had already spent a winter outdoors as a puppy. She was from a long line of happy and healthy Reservation dogs that never saw the vet.
Most of time she slept near the base of a spruce tree, sometimes in the hollow formed in the deep snow around the tree in the dead of winter. There, she curled up with her tail covering the tip of her nose. We saw temperatures that were well in excess of -20f for nights on end.
She would retreat to her house and bed of straw during more prolonged storms with precipitation.
What a specimen she was. She would run behind my snowmobile for miles into the ice fishing lakes we frequented, often in -20f or colder morning temperatures.
As she aged past 10 she spent nights indoors during very cold and inclement weather. She was very active as a hunting dog and property guardian until age 12.