How to Solve Foggy Car Windows on Rainy Days?

[StSamuel]

Press the defogging button, turn on the air conditioning (A/C) switch, set the temperature to the lowest, and turn on the external circulation to defog. Foggy car windows can be cleared by using either cold or warm air, 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 should be noted that warm air should not be used for defogging on rainy days, as it may initially worsen the fog. When the car windows fog up, turn on the external circulation. 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. 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 and the air conditioning is not turned on in time, the humidity from exhaled breath can quickly cause the windshield to fog up. At this point, turn on the air conditioning to blow cold air onto the windshield, using the dehumidifying function to quickly remove the fog. 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, blow warm air onto the glass to quickly raise the temperature of the windshield, reducing the temperature difference between the inside and outside surfaces of the glass and preventing excessive fogging. 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 can cause the outer surface of the windshield to fog up over time. Applying Anti-Fog Spray or Other Preventive Measures: Spray a small amount of defogging agent on the car windows and wipe it clean to remove dirt and stains. While polishing the glass, a thin transparent protective film forms on the surface, effectively preventing water vapor from condensing and forming fog, which is especially useful in cold winters. Alternatives to anti-fog spray include dishwashing liquid, soapy water, glycerin, alcohol, or saline solution. After applying, let it dry and then wipe off any excess with a chamois or soft dry cloth. This will keep the car windows fog-free for several days. Opening Windows for Airflow: If the fog inside the car is not too heavy, open the windows on both sides to create airflow between the inside and outside of the car, reducing the temperature difference and allowing the fog to gradually disappear. The principle of this method is the same as using cold air from the air conditioning. However, the downside of opening windows for airflow is obvious: it cannot be used during rain or snow, on highways, or when the fog is heavy. Rear Windshield Heating: Most cars have a rear windshield heating function, although the button location may vary. Turn on the windshield heating switch, and the fog on the rear windshield will disappear in about a minute.