Ventilate and dry your car - drive with the windows open and the heater on whenever possible. Run the engine and heater together with all doors and windows open for a couple of hours if you can. Give the moisture a chance to dry out. Get some anti-mist cream for your inside windows. Run only a cold blower when it's raining. When you do use the heater open a rear window a little to let the moisture out.
The cause is probably water ingress during the car-wash condensing out on cold windows when you run the heater. At the moment all you're managing to do is to recirculate the moist air; after condensing on the windows the damp is still in the car for the next time.
Peccavi
November 2008