My neighbor does it alot. I could never wash my car by hand if it was colder than 40 degrees. I would take it to a car wash.

 

I'm in upstate NY and after the roads have been salted, I wash my car almost every day it's warm enough for the water not freeze on it. I know, I'm weird.

 

I'll wash my car with water from the hot water heater, but rinse it with water from the hose. That way it gets rinsed off really well, but my hands don't freeze.

 

The water I was washing it with would be frozen before I was half way done. Lol. If I were to wash my car in -30 degree weather, my locks would freeze and I probably wouldnt be able to open my doors if I left it for a bit.