What to Do When the Car Windows Fog Up in Rainy Weather?

[VonBeau]

Press the defogging button, turn on the air conditioning cooling (A/C) switch, set the temperature to the lowest, and turn on the external circulation to defog. Both cold and warm air can be used to defog the 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 the purpose of defogging. The method of using warm air to defog is the same as using cold air, but it should be noted that warm air should not be used for defogging on rainy days as it may initially worsen the fogging. When the car windows fog up, external circulation should be turned on. The reason for car window fogging: 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 of the side 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. Methods to defog car windows: Air Conditioning Cooling: Use the air conditioning's cooling and dehumidifying function to reduce air humidity and remove fog. In summer, especially when multiple people enter the car without turning on the air conditioning in time, the high humidity of exhaled air can quickly cause the windshield to fog up. At this time, turn on the air conditioning to blow cold air onto the windshield. Using the air conditioning's dehumidifying function, the fog on the windshield can be removed quickly. However, if the humidity is too high and the air conditioning is not effective, slightly open a window to quickly reduce the humidity inside the car. Of course, combining this with the air conditioning will yield faster results. Air Conditioning Warm Air: Use the method of reducing the temperature difference to remove fog. In winter, blowing warm air onto the glass quickly raises the temperature of the windshield, reducing the temperature difference between the inside and outside surfaces of the window, thereby preventing excessive fogging on the windshield. However, it should be noted that the rear and side windows heat up more slowly, so it takes longer to completely remove the fog. Whether the air conditioning is automatic or manual, turning it on helps with dehumidification. The temperature control should not be set to the coldest position, as this may cause the outer surface of the windshield to fog up over time. Applying Anti-Fog Agents for Prevention: Spray a small amount of defogging agent on the car windows and wipe it clean to remove dirt and stains from the glass. While polishing the glass, a thin transparent protective film is formed, which effectively prevents water vapor from condensing on the glass and forming fog. This is especially useful in cold winters. Alternatives to anti-fog agents include dishwashing liquid, soapy water, glycerin, alcohol, or salt water. After applying and letting it dry, wipe off any excess with a chamois or soft dry cloth. This can keep the car windows fog-free for several days. Opening Windows for Airflow: If the fog inside the car is not too heavy, you can open the windows on both sides to allow air to flow between the inside and outside of the car, reducing the temperature difference and gradually eliminating the fog. The principle of this method is the same as using cold air from the air conditioning. The downside of opening windows for airflow is obvious: it cannot be used in rainy or snowy weather, on highways, or when the fog is heavy. Rear Window Heating: Most cars have a rear window heating function, though the button location may vary. The function is the same. Turn on the rear window heating switch, and the fog on the rear window will disappear in about a minute.