How to Turn on the Air Conditioning Without Fogging Up the Windows on Rainy Days?
3 Answers
Before it rains, maintain the same temperature inside and outside the car, and turning on the air conditioning will prevent the windows from fogging up. Here are some methods to defog the windows: 1. Wipe off the fog with a towel—this is the quickest way to defog, but you should first stop the car. Wiping the fog while driving can distract you and affect driving safety. 2. Use window ventilation to defog. Since window fogging is caused by the temperature difference between the inside and outside of the car, you can open the window slightly. The incoming air while driving will lower the temperature inside the car, and the fog will naturally dissipate over time. 3. Use the air conditioning's defogging function. Most cars are equipped with a defogging feature—simply turn it on. 4. Apply anti-fog spray in advance as a preventive measure, especially in cities with large day-night temperature differences or frequent rain and snow. You can also make your own defogging solution—common household items like soap or dishwashing liquid applied to the windows can also help defog them.
On rainy days when car windows are prone to fogging up, I most commonly use the air conditioning to prevent it. After starting the vehicle, I directly press the defogging button—the one with the curved arrow blowing toward the glass. This directs cold air quickly toward the windshield, utilizing the AC compressor to cool and dehumidify, reducing interior humidity and preventing condensation. At the same time, I set the temperature to a moderate level, around 22-25°C, keeping it neither too cold nor too hot to minimize temperature differences, which is more effective than extreme highs or lows. Turning on the external circulation mode is also crucial, as it draws in drier outside air to reduce moisture buildup. Before getting in the car, I briefly wipe off any rainwater on the windows to avoid adding to the moisture source. Occasionally, I crack the windows open for a few seconds to ventilate before closing them and turning on the AC. Combining these habits almost entirely prevents fogging, keeping visibility clear. Regularly cleaning the AC filter also enhances defogging performance, making the overall process simple and safe.
Driving in rainy weather always makes me worry about foggy windows obstructing the view. Proper AC settings are crucial. My routine is to first press the defog button, as cold air blowing directly onto the windshield provides the best dehumidification effect. I set the temperature around 20°C for a balanced approach—not too high to avoid increasing humidity and causing fogging. Using external air circulation mode brings in dry air, preventing moisture buildup from internal recirculation. At startup, I maximize the AC fan speed to accelerate defogging, then reduce it to a comfortable level once visibility clears. If seats or clothing get wet, I wipe them dry beforehand to minimize extra moisture. Occasionally, I use anti-fog spray as supplementary aid, though AC defogging remains the primary solution. These tips help me drive safely, making rainy days less troublesome.
