How to Defog the Car Interior on Rainy Days?

[OSawyer]

The methods to defog the car interior on rainy days are: 1. After starting the engine, turn on the warm air conditioning and adjust it to a higher setting, directing it towards the windshield; 2. Evenly spray a defogging agent on the glass. The reasons for car window fogging are: 1. When humidity is high, the window temperature is lower than the dew point temperature; 2. When the temperature is too low, the surface moisture of the window becomes saturated, and the vapor pressure is lower than that of the surrounding environment; 3. There is a certain temperature difference between the two sides of the window; 4. A large temperature difference exists between the inside and outside of the car; 5. The car floor mats are damp. The impact of window fogging is: It obstructs the driver's view, making the road ahead appear blurry and affecting safe driving.

[VanessaMarie]

Driving in rainy weather with foggy windows is quite a common issue. After years of driving, I've summarized some effective solutions. First, turn on the air conditioning system and locate the defogger button—usually marked with a fan-shaped symbol—which automatically activates the defogging mode. Then, adjust the airflow direction toward the windshield to ensure cold air or external circulation quickly dries the moisture. If the fog is too heavy, I briefly crack open a window to balance humidity by allowing air exchange, preventing persistent fogging. Don’t forget to turn on the rear defogger and side mirror heating functions, especially during heavy rain, as safety comes first. I also regularly clean the inner side of the windows with a damp cloth to remove grease and dirt, since clean glass resists condensation. If the A/C underperforms, it might be due to a clogged filter or low refrigerant—schedule maintenance in advance to avoid emergencies. Adopting these habits can significantly improve driving comfort in rainy conditions.

[Donald]

Foggy windows on rainy days are the most annoying thing, especially during traffic jams when it easily obstructs visibility. I usually handle it simply by first pressing the defog button on the air conditioning control panel, which activates the cold air and directs the vents toward the windshield. Then, I quickly crack open a small window, like leaving a gap on the left side for five or six seconds, to let fresh air in and balance the humidity. After that, I slightly increase the interior temperature to help the fog dissipate faster, but I avoid blowing warm air to the point of sweating, as it would make me even more uncomfortable. On the highway, I turn on the defog mode earlier for safety—better safe than sorry. I also remind myself not to frequently switch between recirculation and fresh air modes, focusing instead on controlling the settings. Developing a habit of checking the windows and ventilation before driving helps avoid last-minute panic and potential accidents. These methods are quite easy to follow and hassle-free.

[LaCassidy]

The key to defogging your car lies in quick action and safety first. I turn on the air conditioning in defog mode, adjust the airflow to blow directly onto the windshield, and it usually works in seconds. For severe fogging, slightly opening a window to balance air humidity provides immediate relief. Don’t overlook the rearview mirror heating function—poor visibility in rain is too dangerous. Keeping the front windows clean also effectively prevents fogging; wiping the inside glass monthly avoids emergencies. The whole process is straightforward—don’t overcomplicate it.