Why Does Car Glass Fog Up in Summer?

[Thomas]

There are several reasons for car glass fogging up in summer: Window temperature below dew point: At a certain air humidity level, when the window temperature is lower than the dew point, condensation forms on the window surface, which is the commonly observed fogging phenomenon on the windshield. A temperature difference exists between the two sides of the window. When the indoor air humidity is relatively high and the air temperature is also high, water droplets easily condense on the glass. Low air conditioning temperature inside the car causing a large temperature difference: The low air conditioning temperature inside the car leads to a significant temperature difference. Additionally, improper air conditioning vent direction contributes to this issue, such as when the vents are directed at the windshield and the side windows.