Hyundai Repair: windshield fogging up on outside, air registers, interior temperature

Question
Recently my 2010 Hyundai windshield and side windows have been fogging up on the outside. Only way to get rid of it is to put on the wipers, even when not raining. occurs when just stopped raining and is damp outside. ???

Answer
Hi, Paul.  Water condensing on a windshield occurs via the same mechanism whether inside or outside.  The amount of water air can hold depends on the temperature of the air.  So if warm air with a high relative humidity (such as after a rain) contacts a cooler object, the resulting cooling of the air causes water to condense on that object.

So, in your case, you've cooled the windshield to the point where water condenses on it.  Since you cannot change the humidity of hte air outside the car, there are two avenues you can take to prevent this from occurring.  If you're using the defrost registers, you can switch to the floor or dash/face air registers to try to direct the cool air away from the windshield.  If you're not using the defrost registers, your only other option is to raise the interior temperature of the passenger compartment.  Ultimately, if you're to the point where you'd rather not raise the cabin temperature, you'll need to use the wipers to keep the windshield clear of the condensation.