What Causes Car Windows to Fog Up in Summer?

[LaLevi]

Reasons for car window fogging: 1. Temperature difference between inside and outside the car: Due to the temperature difference between the inside and outside of the car, windows are prone to fogging. The reason is that the window glass, being in contact with the outside, has a lower temperature, causing water vapor inside the car to condense on the glass and form fog. 2. Window temperature below the dew point: When the air humidity is constant, if the window temperature is lower than the dew point, condensation is likely to form on the surface of the window, resulting in the common fogging phenomenon on the windshield. 3. Temperature difference between the two sides of the window: If the temperatures on both sides of the window are different, the surface water vapor pressure on the cooler side will be lower than the surrounding environment's vapor pressure, causing water vapor to gather on the glass surface and form tiny water droplets, resulting in the usual fogging.