If you get into the car wet or damp then whack the heating on, all the moisture will leave you clothes etc and stay in the air inside the car. If you don't open the window slightly on the journey it will stay inside. Then when the air temp cools as it sit's there overnight it will condensate onto all the cold surfaces, mainly the windows.
So you need to remove the moist air at some point to stop it happening over and over again, aircon will do this but so will opening your window a touch even if it's cold and raining outside. Only has to be an inch or so down.
If your anything like my misses (not being sexist) then you'll get in the car then whack the heaters onto MAX and cook yourself all the way home. This won't help
Worth a go
Failing that, your letting moisture in overnight or when it's stood, which could be an issue, but unlikely I would say.
Sam