Should You Use Recirculation or Fresh Air Mode for Defogging in Rainy Days?

[MarianaLynn]

Whether to use recirculation or fresh air mode for defogging in rainy days depends on the specific situation. If using air conditioning for defogging in summer, the driver can switch the air circulation mode to recirculation to reduce air humidity. In winter when using warm air for defogging, the driver can first adjust the air circulation mode to fresh air to minimize the temperature difference between inside and outside the car, wait a few minutes, and then switch to recirculation mode. However, in special circumstances such as traffic jams or heavy dust, it is recommended to use recirculation mode. Summer defogging method using air conditioning. First, press the AC switch button, activate the front windshield defogging button, set the temperature to the lowest, then adjust the fan speed, and the fog on the front windshield will disappear. If fog is also found on the rear windshield and side mirrors, turn on the rear window heating button while defogging the front windshield to remove the fog as well. Winter defogging method using warm air. If the car has just been started, do not turn on the air conditioning immediately. Wait for the engine to warm up for a few minutes until the water temperature rises, then start heating, set the fan speed to maximum, and activate the front window defogging button. The fog will disappear after a few minutes.

[SanAdalynn]

On rainy days, the car windows tend to fog up as soon as I get in. After driving for so many years, my go-to solution is turning on the external air circulation. Why? Because internal circulation just recirculates the humidity inside the car, not only failing to clear the fog but making it worse. External circulation brings in outside air—even though it’s humid outside too, it still dries faster than the air inside. Pair it with the AC’s dehumidifying function, press the AC button, and the fan starts blowing loudly—the windows clear up quickly. Remember not to just turn on the cold or hot air; also adjust the airflow direction toward the windows. Back when I used to help friends fix their cars, I saw too many people stuck with foggy windows because they used internal circulation, wasting time and increasing accident risks. Make it a habit to set the external circulation as soon as you start the car—safety first. Regular maintenance of the AC system is also crucial; replacing the filter costs little but saves a lot of hassle. In short, don’t be lazy and rely on internal circulation—it’s not worth it.

[DelJordan]

As a frequent long-distance driver, I find rainy days particularly annoying due to fogged-up windows. Experience has taught me that using the external air circulation mode is the most reliable. While internal circulation does help maintain a stable temperature inside the car, it traps moisture, causing windows to fog up faster—especially when passengers bring in rainwater. My routine is to immediately activate the defogging mode with the AC on startup, select external circulation, and set the fan to medium for a few minutes until the fog clears. Once, while driving family back home, I mistakenly chose internal circulation, and the worsening fog nearly caused an accident with an obstacle. That incident was a wake-up call. I also make sure to avoid smoking or eating in the car to minimize moisture and regularly clean the AC vents. External circulation keeps things safe and hassle-free—clear visibility is key for focused driving.

[BenjaminAnn]

Safety always comes first when I'm driving, and using the external air circulation is a must for defogging on rainy days. Internal circulation causes moisture to accumulate inside the car, making it harder to clear the fog and even worsening the situation, especially since the outside air is slightly drier on rainy days and can absorb moisture more easily. Set the air conditioning to external circulation, press the defog button, and turn the fan to the highest setting for immediate results. Don't take the risk by experimenting with internal circulation—excessive fog can blur your vision and easily lead to accidents. Remember to check that the air conditioning filter isn't clogged.