I used to live in Buffalo and had no garage so I would take my old car to a pull in wash it yourself garage in about 0 degree temps with only some heat lamps to make sure the water didnt freeze on the paint while I washed it. The only struggle was not slipping on the snow which built up in the garage while washing the car
It actually brings back some fond memories meeting other insane people who would wash and detail in that place, in that weather