What wind should I open when the car glass fogs on rainy days?

The car glass is foggy in rainy days, so turn on the air conditioner. Cold air defogging: The most common way to fog when driving in rainy days is to turn on the air conditioner and blow the front windshield directly. In this way, when the cold wind blows on the glass, the fog will soon disperse, and the effect will be quick and direct. This is because cold air blows on the glass, forming a "cold film" on the surface of the glass to prevent carbon dioxide from condensing on the glass and achieve the effect of defogging. Window convection: If there is not much fog in the car, you can open a gap in the windows on both sides to make the air inside and outside the empty car form convection, so that the temperature difference decreases and the fog slowly disappears. The principle of this method is the same as that of air conditioning, but it does not increase fuel consumption. The disadvantage of window convection is very obvious, which is not found in rainy and snowy weather, highways and foggy days. Opening the window will lower the temperature inside the car.