Washed my old 4x4 about 30+ years ago at 9000' in the Rockies, three in the morning, about 15 degrees, in 2 feet of snow, just me and the dog (she didn't really help much). Short sleeved t-shirt, 10th Mtn boots, and BDU pants. Just for the fun of it.
EDIT: With a freaking bucket and wash cloth and hand towels lol Nothing else to do. Man it looked good though, for about 30 seconds once I drove it.