How to Deal with Fogging on the Outside of Car Windows on Rainy Days?
3 Answers
Fogging on car windows can easily lead to traffic accidents. Generally, fogging occurs due to two reasons: the window temperature being below zero or a temperature difference between the two sides of the window. Solutions include applying anti-fog spray, using the air conditioning's cooling function, or using the air conditioning's heating function. Below are methods to prevent window fogging: 1. Preventive measures such as applying anti-fog spray. Spray a small amount of anti-fog agent on the car window and wipe it clean to remove dirt and stains. While polishing the glass, a thin transparent protective film is formed, effectively preventing the condensation of moisture on the glass and the formation of a fog layer, especially suitable for cold winters. Alternatives to anti-fog agents include dishwashing liquid, soapy water, glycerin, alcohol, or saltwater. After drying, use chamois or a soft dry cloth to remove excess fibers, ensuring the car glass remains fog-free for several days. 2. Air conditioning cooling method. Use the air conditioning's dehumidification function to reduce air humidity and remove fog. In summer, especially when multiple people enter the car without turning on the air conditioning promptly, the exhaled air's high humidity can quickly cause the windshield to fog up. Turning on the air conditioning to blow cold air onto the windshield and using the dehumidification function can quickly remove the fog. 3. Air conditioning heating method. Use the method of reducing temperature differences to eliminate fog. In winter, blowing warm air onto the glass with the heating function can quickly raise the windshield's temperature, reducing the temperature difference between the inner and outer surfaces of the window glass, thereby preventing excessive fogging on the windshield. The rear and side windows heat up more slowly, so it takes longer to remove all the fog.
On rainy days when the windshield fogs up, I usually turn on the AC button first, set the temperature to the lowest, and then press the front defroster button. This trick works much better than just wiping the glass! Remember to direct the air vents toward the windshield and turn on the external circulation to balance the humidity inside and outside the car. If the rear window fogs up, don’t worry—just press the heating wire switch and wait three minutes for it to clear up. Once, when dropping my kid off at school, I tried applying soapy water and wiping it dry—it actually kept the fog away for two hours, but the wipers tended to slip, so use it carefully. The key is to change the cabin air filter regularly—replace it every six months during humid seasons, and with less moisture from breathing inside the car, the windshield will naturally stay clear.
Fogging on rainy days is essentially caused by temperature differences. When the car windows are colder than the air, moisture tends to cling to them. I usually turn on the air conditioning for ten minutes before heading out to dehumidify, so the glass stays clear when I get in. During traffic jams, closing the windows and turning on the AC is the safest way to prevent fogging—opening them just lets more humidity in, making it worse. An old trick from my hometown drivers is mixing dish soap with water at a 1:10 ratio and wiping the windows—it’s cheap and works decently, though heavy rain means reapplying often. If your car has heated side mirrors, don’t forget to turn on the rear window defroster too—rear visibility is just as crucial for safety.
