Small spaces, deep insulation, tight entrances, and shelter from the wind are how every animal in the world survives cold winters, from mice and squirrels, to fox, raccoon, possum, and groundhog.
The dog house, above, is a complete mess. The space underneath the house should be insulated with solid Styrofoam and blocked off, the sides and roof should be paneled with thick Styrofoam or else double-walled with insulation in between, and the entryway should be one fourth the size of what we see here -- 8 inches by 9 inches would be more than plenty for a dog this size. The inside of this dog house should be packed with deep straw. A chute entrance, or at least a small cloth or rubber flap, would go a long way towards cutting wind and heat loss.
Modern plastic crates mean almost any dog can be kept safe and comfortable inside a warm house at night, or for hours at a time during the day. My own dogs have access to the outside whenever they want, can sleep in heated dog houses inside a stone garage that is part of the house whenever they want, and are always brought inside and crated in the laundry room at night.