Reasons for Fogging on Car Windows When Exiting the Garage

[DelPreston]

Because the garage temperature is relatively low and there is humidity underground, when the car exits, the higher external temperature causes fogging due to the temperature difference. Below are related solutions: 1. Reduce the temperature difference: Allow the car to fully adapt to the higher external temperature. Once the moisture evaporates, fogging will naturally stop. When parking, open all the car doors and windows, which can quickly alleviate the issue. 2. Air circulation: If you need to drive away urgently, open the windows to allow air flow. The wind will quickly remove the moisture accumulated during garage storage, and the fog will dissipate naturally within a few minutes.

[VanLily]

The fogging on the car windows when exiting the garage is mainly due to the significant temperature difference. The garage environment is warm, like a small greenhouse, with relatively high air humidity. When you drive the car out, the cold outside air suddenly hits the windows, causing the surface temperature of the glass to drop rapidly. The warm, humid air inside the car comes into contact with the cold glass, causing the water vapor to condense into tiny droplets, forming fog. This is similar to my previous winter driving experiences, especially when there are more people in the car or more breathing, making fogging more likely. To quickly resolve this, you need to turn on the air conditioning's defogging mode, direct warm air at the windows, or open the windows slightly to allow air circulation and reduce humidity. Don’t underestimate fogging—it can obscure visibility and is very dangerous while driving, particularly during early mornings or evenings when light is dim. It’s advisable to open the windows for a while after entering the garage in winter to ventilate and reduce humidity buildup inside the car. This way, fogging is less likely when you exit. Developing this habit can save a lot of trouble.

[DelKennedy]

Fogging on windows is a common issue. The temperature inside a garage is high, like an incubator, with air carrying moisture from our breath and residual dampness. When the car is driven outside and encounters the cold outdoor temperature, the windows cool down rapidly. At this point, the moisture in the warm air condenses on the cold windows, forming fog—similar to how water droplets form on a hot cup in cold weather. Having driven for several years, I know prevention is simple: press the defog button immediately after starting the car, use the air conditioner to blow warm or cool air (depending on the weather) to clear the fog. Regularly ensure the car interior isn’t cluttered with items like wet shoes or food residues to maintain dryness. Before entering the garage, turn off the heater for a while to balance the temperature. If fogging occurs frequently, check if the window seals are aged or leaking, or if the air conditioning system is functioning properly. Safety comes first—don’t drive if the fog is too heavy; stop and handle it. These small habits make a big difference.

[LaAriel]

The main cause of fogging is temperature difference and humidity. The garage is warm, the glass is cold, and water vapor condenses easily to form fog. Turning on the air conditioning will solve it.