How to Quickly Solve Fogging on Car Windows in Rainy Days?

[NathanAnn]

When the car windows fog up on rainy days, you can turn on the front window defogging mode, set the fan speed to maximum, turn on the A/C switch, and adjust the air conditioning temperature to the lowest setting. Here are the ways to deal with foggy car glass on rainy days: 1. Spray the defogging agent evenly on the glass surface and wipe it clean with a dry towel. Principle: Using the method of surfactants, a protective film is left on the glass surface, changing the surface tension of water molecules, causing fog droplets to condense into large water droplets, thus not obstructing the view. 2. Turn on the car's defroster. Principle: Use dry, cold air from inside the car to blow against the front windshield, making the temperature inside and outside the car glass uniform, forming a dry gas barrier, thereby preventing condensation of humid air inside the car and avoiding fogging. 3. Open the window to let the wind clear the fog. Principle: Lowering the temperature inside the car makes it harder for moisture to condense.

[LilahFitz]

I'm the kind of seasoned driver who gets flustered on rainy days, and window fogging is all too common. Let me teach you a three-step method: immediately turn on the AC button, then press the front windshield defogger button—that's the one with a fan-shaped symbol and wavy arrows—and switch to external circulation mode. At this point, you'll hear the fan whirring as cold air blows directly onto the glass, and the fog will clear in less than 20 seconds. Remember not to use internal circulation, as the moisture from passengers' breathing will only make it worse. If the fog is too heavy, you can quickly wipe the inside of the glass with a clean chamois cloth as an emergency measure, but don’t do this while driving! Keep a pack of defogging wipes in the glove compartment for quick use when needed. Also, don’t set the AC temperature too low—around 22°C is the most comfortable and effective, otherwise you’ll shiver and get distracted. Safety comes first when driving in the rain!

[JaceLynn]

I've been driving for twenty years, and nothing scares me more than foggy, unclear roads on rainy days. Window fogging is essentially moisture condensation, and it needs to be dealt with quickly: after starting the car, turn directly to the hot air setting, set the temperature to the highest, crank the fan to maximum, and simultaneously press the AC button for dehumidification—don’t worry about fuel consumption, safety comes first. The key is to select the front windshield air vent mode, allowing the hot air to evenly heat the glass. If the side windows fog up, turn the vents toward the windows. When there are many people in the car, avoid opening windows for ventilation, as outside moisture will only make it worse. In an emergency, cracking the sunroof slightly can help, but don’t try this in heavy rain. I make it a habit to check the cabin air filter every season and replace it immediately if it’s dirty—this improves defogging effectiveness. Remember, don’t turn off the AC right after the fog clears; keep the airflow going for a few minutes to prevent recurrence.

[LaGabriel]

I've encountered this issue multiple times, and simple solutions work effectively. The principle is that moisture inside the car condenses into fog when it hits the cold glass, so first turn on the AC to dehumidify. The easiest way is to press the front defroster button (the fan-shaped one) on the center console – it automatically balances the temperature difference inside and outside. For manual operation, select the windshield mode + external air circulation, with medium fan speed. Avoid directing the vents straight at your face, as the cold air can be uncomfortable. Keep a defogging spray handy; applying it with a cloth on the inner side of the glass prevents fogging for half a day. For rear windshield fogging, press the heating button, and the red heating lines will gradually clear the fog. Don’t trust online hacks like rubbing soap – they leave streaks and are riskier. If fog appears, slow down and pull over before handling it. Safety always comes first.

[MacOlive]

I have a deep understanding of window fogging issues. The first instinct is to turn on the AC by pressing the AC button and defogger combo—most modern cars have this shortcut that simultaneously activates cooling and windshield venting. Adjust the vents to point at the front windshield and switch to external air circulation mode; it usually clears up in about 30 seconds. For the rear window, use the heating wire function by pressing the rectangular button with wavy lines. In an emergency, wiping with a dry tissue works best, but remember to do it while parked. A pro tip: pre-cool the cabin by running the AC a few minutes beforehand to lower humidity when entering. I’ve also found that applying anti-fog film reduces fogging by 90%—it’s just a few dozen RMB on Taobao and can be DIY-installed. Regularly cleaning interior glass with a glass cleaner minimizes oily residue, naturally reducing condensation. Installing anti-fog rain deflectors also helps with ventilation.

[Geoffrey]

When it comes to defogging in rainy weather, my approach is prevention first. Every time I wash my car, I use a dedicated glass cleaner to wipe the interior windshield, removing oil films to prevent fogging. I always keep anti-fog wipes in the car—a quick wipe at a traffic light does the trick. Before driving, I open the windows for a minute to ventilate and disperse moisture. On rainy days, as soon as I get in the car, I start by turning on the AC for cooling, setting the temperature around 22°C, and selecting the windshield defogging mode. Remember to turn off the recirculation mode, or else moisture will be trapped inside, making it worse. If the rear window fogs up, use the heating function. For a long-term solution, check the cabin air filter and replace it immediately if it's dirty; keep a bag of desiccant in the car to absorb moisture. Once during a heavy rainstorm on the highway, my windows fogged up—I slowly changed lanes and stopped in the emergency lane to deal with it. Safety comes first—never wipe the windows while driving!