If the interior of the passenger compartment has a high humidity the windows will mist up more than a low humidity.
You may consider leaving a small gap at the top of the windows whenever you can to let natural ventilation clear away the damp atmosphere - you do not need to see the moisture - it will be in the seats and the carpet.
If you are able - park it up with all the doors left open for a couple of hours - wrap up warm and go for a spin with the windows open and the heater on full-blast but set to COLD.
You will still get a bit of misting now and again but no more than any car - but you must dry it out to get rid of the excessive misting - when you run the blower full blast open a window else you just move the moisture around inside the car - it needs to be let out.
Good luck...
Peccavi
January 2010