What causes condensation inside a car windshield?

Condensation inside a car windshield occurs when warm, moist air inside the vehicle comes into contact with the cooler surface of the glass. This temperature difference causes the moisture in the air to cool and condense into water droplets. Factors such as high humidity levels inside the car, particularly from passengers' breath or wet clothing, can exacerbate the issue. Using the vehicle's defrost setting can help reduce condensation by circulating dry air and warming the glass.