Winter Car washing in heated garage

[Bigsyke]

In the summer after replacing alot of the suspension I inspected the frame for rust. I found little, and absolutely none on the body. The car has been in winter climates for 10 years (1995).

However this winter I washed my car about once every 2 weeks in a heated garage. I didnt have a parking space inside so I would park outside. Im thinking this was a bid no-no because now its as if somebody took a paint ball gun, and shot my car with rust paint bullets. You can see spots littered on the doors and rear quarter panels of rust hazing.

Its a brown residue that wont buff off. Ive also noticed other parts of the body are starting to flake off, and suddenly it seems this body is rusting at 10x the rate.

Could it be from the sudden drop of temps once I roll the car outside, which is lifting up the paint?

Anyone else who washes their car in 7*f temps in a heated garage has this problem?