How to Deal with Fogging on the Outside of Car Windows on Rainy Days?
3 Answers
When car windows fog up on rainy days, the following methods can be used to address the issue: 1. Preventive measures such as applying anti-fog spray. Spray a small amount of anti-fogging agent on the car windows and wipe it clean to remove dirt and stains from the glass. 2. Air conditioning cooling method. Utilize the air conditioning's dehumidification function to reduce air humidity and eliminate fog. 3. Air conditioning heating method. Use the method of reducing the temperature difference to remove condensation. Fogging on car windows during rain occurs under two conditions: high humidity and low temperature. When the air humidity is at a certain level and the window temperature falls below the dew point, condensation forms on the window surface, which is the fogging phenomenon we often see on the windshield. Additionally, when there is a certain temperature difference between the two sides of the window, and the saturated vapor pressure of the surface moisture on the cooler side is lower than the surrounding environment's vapor pressure, moisture gathers on the glass surface, forming tiny droplets that appear as fog. If the dew point is above zero degrees Celsius, fogging occurs; if it is below zero degrees Celsius, frost forms.
On rainy days when the outside of the glass fogs up, I usually just swipe it with the wiper—simple, effective, and free. Cool weather plus heavy rain makes the windshield prone to fogging up outside because the low temperature causes moisture to condense on the glass, forming a thin film. Don’t worry, it’s common and easy to handle—just turn on the wiper and a gentle swipe will clear the fog. If the fog is too thick to wipe away, I turn on the AC in cold mode and blow it directly at the glass for a few seconds to dry it quickly. Remember not to use the heater, as it can worsen the situation and even create more condensation. Also, developing a habit of regularly cleaning the glass is key—using water and a cloth to wipe the surface can reduce fogging frequency. If this happens while driving, don’t panic—slow down safely and focus on the road. Before heading out in the rain, I also check the wiper quality and replace worn ones to avoid issues mid-drive. These tips come from years of driving experience—give them a try, they really work.
When the car windows fog up in rainy weather, I immediately turn on the wipers to clear the water droplets or quickly activate the air conditioning in cool mode. This method is efficient and hassle-free. Fogging occurs due to the significant temperature difference between the inside and outside of the car, causing moisture to condense on the exterior surface, which can dangerously obstruct visibility, especially on highways where I take extra care not to get distracted. For prevention, I often keep the interior dry, avoiding leaving wet shoes or umbrellas that retain moisture. Opening the windows for a few minutes before driving can also prevent major issues. If the wipers don’t clean properly, I check if the rubber blades need replacement or cleaning, and adding some windshield washer fluid can make them glide more smoothly. Safety is the top priority—don’t rush; it’s safer to pull over and handle the situation. Sharing this experience to remind everyone not to overlook daily minor maintenance.
