If your car is currently the color “winter gray-brown” instead of whatever you paid for at the dealership, you’re not alone. Let's see what the experts have to say about car washing in the middle of winter. According To Those In The Know, Vehicle Washing During The Winter Is All About A Magic NumberThat magic number is apparently 40 degrees. Touchless car washes are your safest bet in winter, since they rely on high-pressure water and heated air instead of brushes that can trap moisture. Here's What Happens With A Carwash At 15 DegreesFirst, the water wouldn’t even wait for you to leave the car wash.