What Causes Condensation Inside the Car in Summer?

[CarmenFitz]

Condensation inside the car in summer is caused by temperature differences. Temperature difference leads to dew formation: When the humidity in the air is constant, if the temperature of the car window is lower than the dew point, dew will form on the surface of the window. This is the fogging phenomenon often seen on the windshield. Temperature difference leads to fog formation: When there is a certain temperature difference between the two sides of the window, and the saturated vapor pressure of the water on the cooler surface is lower than the vapor pressure of the surrounding environment, water vapor will gather on the glass surface and form tiny water droplets, resulting in fog. Solution using air conditioning cooling: Use the air conditioning's dehumidification function to reduce air humidity and remove fog. Solution using air conditioning heating: Blow warm air onto the glass to quickly raise the temperature of the windshield and reduce the temperature difference between the inner and outer surfaces of the window, preventing excessive fogging on the windshield. The main reasons for condensation inside the car are high humidity inside the car and low temperature outside. In summer, especially when multiple people enter the car and the air conditioning is not turned on promptly, the high humidity from exhaled breath can quickly cause fogging on the windshield. At this point, you can turn on the air conditioning to blow cold air onto the windshield and use the dehumidification function to remove the fog on the windshield quickly.

[WyattAnn]

In summer, condensation often appears inside the car mainly because the outside weather is extremely hot. When I turn on the AC to cool down the interior, the windows suddenly become foggy and obstruct the view. This frequently happens when driving friends around—more people exhaling moisture combined with the AC cooling the glass creates a temperature difference that causes water vapor to condense. I remember once on the highway under scorching sun, the windshield fogged up shortly after turning on the AC, startling me to immediately hit the defrost button. For prevention, it helps to open windows briefly before driving to ventilate, avoid setting the AC too low, and direct air vents toward the windows. High humidity conditions, like after heavy rain, make this more likely, so extra caution is needed for safe driving to avoid accidents due to obscured vision. Parking in shaded areas when possible reduces temperature differences, and good car sealing minimizes moisture seepage.

[MorganDella]

The fogging inside the car in summer is caused by the large temperature difference between the inside and outside: When I turn on the air conditioning, the interior becomes cold and the glass cools down, allowing hot and humid air from outside to enter and condense into water droplets. As an experienced driver, I understand that this significantly affects driving, especially when there are many people in the car or during rainy days with high humidity, making fogging more likely. It's essential to immediately activate the defogging mode or adjust the air vents to blow on the glass to prevent the fog from causing delays. The reason is simple—the air conditioning's dehumidification effect can't keep up with the external humidity. For long-term prevention, it's advisable to check if the air conditioning system is functioning properly and ensure the filters are clean for effective dehumidification. If fogging occurs repeatedly, it might be due to poor car sealing allowing moisture to seep in. Safety first—when fogging occurs, slow down and pull over to handle it safely, avoiding the risk of driving under such conditions.

[Games]

When the air conditioning is on in the car during summer, sudden fogging on the windows obstructing vision is all due to temperature and humidity. Whenever I encounter this, I quickly press the defog button or slightly open the window for ventilation to let the cold air blow away the moisture. For prevention, turning off the air conditioning before parking to let the temperature adjust gradually helps a lot. This is more likely to happen when there are many people and high humidity inside the car, so pay extra attention to setting the vents to blow directly at the windows.

[JasperFitz]

Fogging inside the car is common during hot summer weather, and I've personally experienced dangerous moments with blurred vision. When the air conditioning is too cold, the temperature difference between inside and outside causes moisture to condense on the windows. It's recommended to check if the defogging function works before driving and use recirculation mode to reduce external humidity. More passengers mean higher humidity, making fogging more likely – address it immediately when it appears while driving. Regular window cleaning helps prevent fog from adhering easily.