What Causes Windshield Fogging in Summer?

[DonovanFitz]

In summer, car windshield fogging occurs due to the low temperature setting of the air conditioning, which creates a significant temperature difference, combined with incorrect airflow direction settings, such as directing the airflow toward the front windshield or the side windows. The cold air lowers the temperature of the glass, and when this cold glass comes into contact with the hot and humid outside air, it easily forms condensation on the outside surface. Unlike winter fogging, summer fogging mostly occurs on the outside of the windows and tends to appear in clusters rather than covering the entire window surface. This is the key difference between summer and winter fogging. Solutions: For manual air conditioning systems, simply turn the fan speed to maximum, activate the A/C switch, set the temperature to the lowest, and press the front defogger button to gradually clear the fog. For automatic air conditioning systems, press the AUTO button, set the temperature to the lowest, and press the front defogger button. For models equipped with rear window defogging, pressing the rear defogger button can speed up the process and prevent further fogging.