Insulation, Radiant and Vapor Barriers - How to get rid of mold/moisture in garage?

I found mold under the two windows in my garage recently. It must be caused by the condensation during many of the cold nights (0 – 20 F).

My 1st question is what is the best way to get rid of the moisture brought in by the snow on the roof/tires of my cars?

I don’t want to open the garage doors or the windows unnecessarily, since the garage is attached and there is a bedroom on top of the garage. My dehumidifier doesn’t work when the temperature is below 60F. The windows are double-pane windows.

My 2nd question is: if I cannot lower the humidity, how to get rid of the mold and be sure it will not come back next winter?

Any suggestions?

hi
good question.
Either you leave your car in the driveway.
or you clean up the garage once the snow as melted from the car.or have some garage heather install.
I live up north for 40 yrs and i had a garage and NEVER had car in garage and my temp would go to -40 and more
Why spoil it :D
pg

You might consider a "Passivent"
They work automatically without power.
It will open when the humidity level is high.
When it returns to an aceptable level it will close by itself.
We use them in bathrooms (after removing the fans)