What to Do When the Car Fogs Up in Rainy Weather?

[McAlexander]

Here are the methods to deal with car window fogging in rainy weather: 1. Preventive measures such as applying anti-fog spray: Spray a small amount of anti-fog agent on the car windows (inner side) and wipe them clean to remove dirt and stains. While polishing the glass, a thin transparent protective film is formed on the surface, which effectively prevents the formation of fog caused by moisture condensation, especially suitable for cold winters. Alternatives to anti-fog spray include dishwashing liquid, soapy water, glycerin, alcohol, or salt water. After drying, wipe off excess residue with chamois or a soft dry cloth to ensure the car windows remain fog-free for several days. 2. Air conditioning cooling method: Use the air conditioning's cooling and dehumidifying function to reduce air humidity and eliminate fog. In summer, especially when multiple people enter the car, if the air conditioning is not turned on promptly, the high 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, the fog on the windshield can be removed quickly. However, if the humidity is too high and the air conditioning is not effective enough, slightly open a window to rapidly reduce the humidity inside the cabin. Of course, combining both methods can yield faster results.

[Gray]

I've been driving for over a decade and often encounter foggy windows on rainy days. I immediately turn on the air conditioning system, locate the dedicated defogging button, and press it to activate the automatic function. Setting the fan speed higher and directing it toward the windshield improves the effect. If there's no automatic function, I adjust the temperature—cold air usually dehumidifies faster, but on rainy days when the air is humid, I switch to external circulation to let fresh air in and reduce interior humidity. Regular maintenance is also important: cleaning oil stains from the inside of the windows and applying anti-fog spray can provide long-lasting protection. Avoid wiping with a cloth while driving, as it can be distracting and dangerous. When visibility is poor due to rain, slow down and wait for the fog to clear before accelerating—it’s much safer. Developing these habits has made driving much more reassuring.

[JohnLynn]

I just got my driver's license, and I always panic when the windows fog up during rainy drives, making it hard to see the road. Later, a friend taught me: just press the defogging button on the front windshield, and it automatically turns on the AC to blow air and clear the fog—simple and hassle-free. You can adjust the temperature yourself; I find cooler settings work better. Opening the window slightly for ventilation helps during heavy rain, but you don’t want rainwater getting in. Safety first—deal with fogging immediately when you notice it. I’ve also tried stopping to wipe the windows, but don’t do it while driving. After using it a few times, I got the hang of it, and now I can usually solve the problem with just one button press, making things much easier.

[RiverFitz]

Driving with foggy windows on rainy days is too dangerous. I've experienced a near-accident because of it. Now, I turn on the air conditioning to defog as soon as I get in the car, with higher fan speed to quickly disperse the fog. I set the temperature to a moderate level and use the external circulation mode since humidity is high on rainy days, keeping it on longer to dehumidify. Prevention is key—regularly clean the windows and use anti-fog products. For safety, slow down immediately if fog appears and pull over to deal with it. Don't ignore it; maintaining clear visibility ensures steadier driving.