When it rains, why does the vehicle or car window glass becomes foggy?

Condensation forms when warm, humid air contacts a cold surface. Water vapour is in the air all around us and warmer air can hold more vapour. As air cools, it contracts and its moisture condenses. When the temperature drops, the first place you will see any condensation is on the windows. In the rainy season the temperature drops and the moisture gets deposited on the window glasses making them foggy. You have to use wipers to clean up the foggy windows.

Your windows are the coldest surfaces indoors. During colder months, indoor air is much warmer and holds more moisture than outdoor air, which is colder and dry. Warm, humid indoor air cools and contracts; as it contacts the cooler windows, the moisture condenses on the glass.


Simply Easy Learning

Updated on: 10-Oct-2022


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