Where I go (Grand Prix Wash), there's one guy wiping your car down. He spends between 5 and 10 mins on it - and they are great - very detailed guys. They now I always toss a five at them, so they fight over the yellow car (you can hear them arguing in spanish over who's turn it is por la amarillo carro

 

The ambient temperature on the way to work this morning read -23C. On the way home it was a balmy -18C. I'm not about to wash the car in those temperatures by any method - and the car is filthy with salt and other assorted frozen highway crud.

However, any time the temperature is above about -10C, it can go through a touchless wash and any time the temperature is above 0C, I'll wash it by hand. No need for buckets of warm water etc. Just one size fits all woollen gloves under dollar store vinyl kitchen gloves, the pressure washer (relatively low power), shampoo, wash mitt and chamois - oh, and remember to drain the outside plumbing when finished

I'm with Irish8, I have also washed mine in the rain - just not in freezing rain