Should the Car Air Conditioner Be Set to Internal or External Circulation on Rainy Days?

[DelVictoria]

It is better to use external circulation in the car on rainy days. Here is the relevant information: Specific reasons: On rainy days, the weather is cold, and both side windows may fog up, affecting the driver's visibility. Therefore, it is best to first use external circulation and adjust the airflow direction toward the windshield. Using external circulation can expel the steam exhaled by passengers out of the car, while the outside cold air is less likely to condense. Generally, with the windows closed, internal circulation means the air inside the car is recirculated under the action of the fan. Since the passage for outside air is closed, no external air can enter, making the air quite stuffy. External circulation, on the other hand, allows outside air to enter through the opened passage, making the air fresher. Precautions: When the outside air quality is poor or heavily polluted, such as on dusty roads, in congested traffic, or near chemical plants where there are foul odors or unusual smells, use internal circulation to prevent the poor outside air from entering the car. In summer, to quickly lower the car's interior temperature with the air conditioner, internal circulation can be used.