How to Deal with Foggy Windshield on Rainy Days?
4 Answers
Solutions for foggy windshield on rainy days: 1. Apply soap or dishwashing detergent. Soften the soap by soaking it in water, then evenly coat the entire glass surface (must be even). After the soap dries on the glass, remove it with a tissue or newspaper (towels may leave residue). Alternatively, mix water and dishwashing detergent in a 9:1 ratio and spray it on the front windshield and side windows. Let it dry, then wipe clean with a soft tissue. 2. Anti-fog spray. Anti-fog spray not only removes fog from the glass but also forms a thin protective film to prevent fog from forming again. It is a truly effective product for ensuring driving safety. 3. Air conditioning cooling. There are two reasons for foggy windows in summer: low temperature and high humidity. The owner can turn on the air conditioning and blow cold air toward the front windshield, using the dehumidification function to remove the fog. However, if the humidity inside the car is too high and the air conditioning cooling effect is not obvious, slightly opening a window can quickly reduce the humidity. 4. External circulation defogging: Turn on the external circulation for defogging. The correct vent position should be able to blow both the front windshield and the feet or only the front windshield. When windows cannot be opened on rainy days, using the external circulation is also one of the methods for defogging.
The first time I encountered foggy windshield on a rainy day, I panicked as the blurred vision made driving impossible. Later, a friend taught me a simple method: upon entering the car, first turn on the air conditioning defogging mode—that fan-shaped air vent button—and switch to external circulation to let fresh air in, reducing interior humidity. Simultaneously, activate the AC to enhance dehumidification, and the fog will clear within seconds. Cracking the windows slightly can also aid ventilation, but avoid opening them too wide to prevent rain from entering. Fogging occurs due to high interior humidity and the temperature difference between the cold outside and warm inside, causing condensation on the glass. To prevent it, wipe the glass clean before parking and avoid water accumulation on floor mats; regularly check if the air conditioning system’s filter is clean, as a dirty one can hinder defogging. Safety comes first when driving in the rain—handle fogging decisively without hesitation.
I usually prefer hassle-free solutions when driving. On rainy or foggy days, I rely on practical tricks. I turn on the heater to blow air onto the windshield, set the temperature a bit higher, and activate the air conditioner's dehumidification mode—this combo clears the fog quickly. If that doesn’t work, I pull over safely and wipe the glass with a clean cloth. Prevention is key: I use anti-fog spray on the glass every quarter, which reduces fogging on rainy days. I also avoid leaving damp items in the car, like floor mats—I dry them thoroughly before putting them back. Fogging mainly happens due to temperature and humidity differences, so using the external air circulation helps prevent moisture buildup. A budget-friendly trick is cracking a window slightly for ventilation, but be cautious of rain getting in. Once you make these habits, driving becomes much smoother.
Fogging is fundamentally caused by the temperature difference between the inside and outside of the car, where cold, humid air condenses upon contact with warm glass. The most effective method is using the air conditioning's dehumidification mechanism: turn on the AC and switch to the warm air defogging mode (the symbol resembles wind blowing onto the glass), which can quickly absorb moisture, making the fog disappear instantly. Additionally, check if the air filter is clean and perform regular maintenance and replacement to ensure optimal system performance. Using the external air circulation mode can help reduce humidity—avoid using internal circulation as it may worsen fogging. A simple experiment: when the humidity inside the car is high, fogging tends to recur easily. Maintaining a dry environment can prevent this, such as by not placing wet items in the car.
