Why Does Frost Form on the Outside of the Windshield?

[VanCharlie]

Frost forms on both the inside and outside of the car's front windshield because residual heat inside the vehicle causes the glass temperature to be higher than the outside. If the external temperature is too low or it snows, the snowflakes landing on the glass will initially melt. Below is a related explanation: 1. Why frost forms: During the melting process of the snowflakes, when the interior temperature gradually drops to match the outside temperature, the melted snow on the glass begins to freeze. Once ice forms, any additional snowflakes that land on it will not melt but instead cover the ice like a blanket. The moisture on the glass then solidifies into ice beads, forming frost on the windshield. 2. Winter defrosting methods: Turn the car's heating system to the highest setting to raise the window temperature and melt the frost. Activate the A/C mode, and once the interior warms up, switch to the recirculation mode to prevent fogging inside the car. Then, turn off the recirculation to lower the interior temperature. Opening the windows allows internal and external air to circulate, speeding up the melting and disappearance of the frost on the windows.