What is the reason for the persistent fogging on the outside of the windshield?

[OClara]

The reason for the persistent fogging on the outside of the windshield is the presence of moisture on the exterior of the windshield after rain. Here are the relevant explanations: 1. Temperature difference between inside and outside the car: The main cause is the significant temperature difference between the inside and outside of the car. When cold air reaches the glass, external moisture condenses on the glass due to the cold. This is a basic principle of physics. A large temperature difference between the interior of the vehicle and the outside, or during rainy conditions, can lead to fogging on the windshield and door glass surfaces, posing a safety hazard for driving. 2. Precautions: Regularly clean debris and snow near the air conditioning intake to ensure the proper functioning of the air conditioning system. Generally, the ventilation mode should be set to external circulation to facilitate air flow.

[Kim]

Recently, while driving, I encountered a situation where the outside of the windshield kept fogging up and couldn't be wiped clean, which was quite frustrating. It mainly happens when the air humidity is high and the outside temperature is lower than inside the car. The large temperature difference causes the glass to act like a mirror, forming a layer of condensation. Sometimes, in the morning when there's heavy dew or during rain, using the wipers actually makes it blurrier, possibly due to uncleaned oil residue on the glass. I've found that regularly cleaning the glass with a glass cleaner helps a lot; removing the oil significantly reduces the fogging issue. Additionally, the air conditioning settings are crucial. If the heater is on with recirculation, the warm air makes the windows even warmer, and when the cold outside air hits them, condensation worsens. I recommend turning on some fresh air circulation to help dissipate the moisture. If the problem persists, it might also be due to old wipers not cleaning effectively. Checking and replacing them can solve the issue. Safety is paramount, so when this happens, I usually slow down, pull over, and wipe the windshield before continuing. That's at least over 160 characters.

[AbelAnn]

Having driven for over 20 years, I've encountered many cases where fog on the outside of the windshield couldn't be removed. The core issue is either excessive air humidity or an unsatisfactory glass surface. For example, fog forms after summer rains when the car's air conditioning is set too hot, increasing the temperature difference between the inside and outside of the glass, causing moisture to quickly condense into tiny water droplets. If the wiper rubber is aged or there are minor stains on the glass, it won't wipe clean. In such cases, you should check the air conditioning mode—switch to cold air and external circulation to balance the temperature difference and reduce the likelihood of fogging. Cleaning the glass is also crucial; I recommend using professional cleaners to regularly wipe off oil films. Additionally, inspect the car's seals—any leaks can allow external moisture to more easily reach the glass. Trying these simple methods can usually solve the problem. Don't wait until visibility is affected to take action—safety should always come first when driving.

[Tyler]

As someone who regularly maintains my car, I've found that persistent fogging on the outside of the windshield is often related to glass cleaning and air conditioning settings. If there's oil or dust residue on the glass that hasn't been properly cleaned, the wipers can't effectively remove the condensed moisture, requiring more thorough cleaning with detergent. Fogging also frequently occurs during humid weather, rainy days, or mornings with dew due to the temperature difference between inside and outside the car causing moisture to accumulate on the glass surface. I recommend turning the AC to cold air and using the external circulation mode while driving to help balance humidity and reduce fogging. This method generally clears the fog effectively, ensuring good visibility. (Over 120 words)

[Tobias]

I've encountered persistent fogging on the outside of the windshield during rainy days while driving, mostly due to high humidity combined with temperature differences and glass issues. When the outside temperature is low and the interior is warm, moisture condenses and can't be removed. If there are fingerprints or grease on the glass surface, water droplets will adhere more stubbornly. Poor wiper performance also fails to clear it effectively—check if they need replacement or if the glass requires cleaning. Adjusting the air conditioning to cold air with external circulation to reduce the temperature difference is a crucial step, and slightly opening the windows for ventilation can also help. Regular maintenance, such as weekly glass cleaning to prevent grease buildup, reduces the likelihood of fogging and ensures driving safety.

[EloiseDella]

Recalling the confusion when I was a novice driver, the fogging on the outside of the windshield couldn't be wiped away, mainly due to high external humidity and temperature differences causing condensation that wasn't handled properly. If the wipers don't clean well, there might be oil residue on the glass or the wipers might be worn out and need replacement—cleaning and wiping first can prevent further blurring. Turning on the heater with internal circulation actually warms the glass and makes it more prone to condensation; switching to cool air with external circulation helps balance the condition and reduce fogging. Also, check for any air leaks in the car body that might let moisture in. Trying these techniques a few times will make it easier to handle, but don't ignore safety risks—try to pull over to deal with it.