Why Does the Car Get Foggy on Rainy Days?
4 Answers
On rainy days, even during summer, a temperature difference develops between the inside and outside of the car. The outside temperature is lower, while the inside temperature is higher. Consequently, the temperature of the car windows also drops. When the humid air inside the car encounters the cold windows, it condenses into fog. Additionally, the air is more humid on rainy days, and when opening and closing the car doors, water from wet shoes can be brought inside, increasing the humidity in the car and making it more prone to fogging. Here’s a quick solution: Immediately turn on the car’s air conditioning, set the defrost function to maximum, and direct the cold air towards the windows. The fog will typically clear within three seconds.
The reason for fogging inside the car on rainy days is actually quite simple, mainly caused by humidity and temperature differences. After driving for so many years, I often encounter this situation because the moisture in the air is particularly high when it rains, and with people sitting in the car, the humidity inside skyrockets due to the water vapor exhaled. The outside temperature is low, making the glass very cold, and when the warm, humid air inside the car comes into contact with the cold glass, the moisture condenses into tiny droplets, forming fog on the glass. For example, in summer when the air conditioning is on or in winter, the cold air cools the glass faster. This not only affects visibility but can also lead to accidents. To deal with it, I recommend turning on the defogging mode of the air conditioning as soon as you get in the car, directing the airflow toward the glass, or opening the window slightly to allow air circulation. For prevention, keeping the windows clean and avoiding leaving wet items in the car can reduce fogging. Remember, safety comes first, and dealing with fog promptly is more important than any trick.
I pay special attention to the issue of fogging up when driving in the rain, as it directly affects driving safety. Moisture accumulates from both outside and the breath inside the car, and when the windows cool down, water droplets condense, creating a blurry view, which is especially distracting on highways. As an experienced driver, when I encounter fogging, I immediately turn on the air conditioning to blow cold air onto the windows with a higher fan speed to expel the moisture. If the fog is too thick, I slow down and find a safe spot to stop and deal with it. Regular vehicle maintenance is also crucial, such as cleaning the cabin air filter and avoiding eating in the car during rainy days to reduce humidity. Simply put, fogging is the result of the collision between temperature differences and humidity inside and outside the car. Rainy air is saturated with moisture, and fog can form easily if not careful, so developing a habit of checking the windows as soon as you get in the car is key.
Foggy windows on rainy days always bother me, mainly due to excessive humidity. High air moisture, combined with added moisture from human breathing, condenses when the glass temperature drops. I usually turn on the air conditioning's dehumidification function or crack the window for ventilation, which works quite well. For prevention, keeping the windows clean helps.
