What Causes Fogging on the Outside of Car Windows?
2 Answers
Reason: Fogging on the car windshield occurs due to a significant temperature difference between the inside and outside of the vehicle. The carbon dioxide exhaled by passengers contains a lot of water vapor, which condenses into tiny water droplets when it comes into contact with the cold glass. Here are some additional details: 1. Utilize air convection: Due to seasonal temperature variations, the difference between the inside and outside of the car increases. Warm, humid air inside the car meets the cold windshield, releasing heat and condensing, which easily causes fogging. Therefore, you can slightly open a window to allow air convection between the inside and outside of the car, balancing the temperature difference and preventing fogging. 2. Use the air conditioner's warm air: Turn on the warm air setting and direct it toward the windshield to quickly raise the glass's temperature. This eliminates the conditions for warm, humid air inside the car to release heat and condense on the window, thereby preventing fogging.
Fogging on the outside of car windows in cold weather occurs because the glass surface temperature is too low, causing water vapor in the air to condense into tiny droplets. This is especially common in humid conditions or during night driving. As someone who commutes daily by car, I often encounter this issue in the mornings when the interior is warm and the outside is cold—large temperature differences lead to fogging. To maintain visibility, you can first try blowing hot air on the windshield or using the wipers a few times. It’s important to develop the habit of ensuring the automatic defrost system is functioning properly when parking, as severe fogging can dangerously obstruct your view. Also, remember to regularly clean dust and dirt from the outside of the windows to maintain clarity and prevent faster condensation. If fogging happens frequently, check for gaps in the window glass or damaged heating wires. A thorough inspection before long trips can save a lot of trouble.
