Which Button to Press for Foggy Windows on Rainy Days?

[MacBella]

Press the defogging button, turn on the air conditioning cooling (A/C) switch, set the temperature to the lowest, and activate the external circulation to remove fog. Both cold and warm air can be used to defog car windows, but warm air is slower than cold air. The most effective method is to use cold air, which blows dry cold air directly onto the glass, preventing water vapor from condensing on the glass and achieving defogging. The method for using warm air to defog is the same as using cold air, but it's important to note that warm air should not be used for defogging on rainy days, as it can initially worsen the fog. Always use external circulation when defogging car windows. The reason for foggy car windows: There is a certain temperature difference between the inside and outside of the car. If the temperatures inside and outside the car are different, the surface with the lower temperature will have a lower saturated vapor pressure than the surrounding environment, causing water vapor to gather on the glass surface and form tiny water droplets, resulting in fog.