Should You Use Internal or External Air Circulation on Rainy Days?
2 Answers
On rainy days, it is recommended to use the external air circulation in your car. Cold weather during rain can cause fogging on both side windows, obstructing the driver's view. Therefore, it is best to first use the external air circulation and adjust the airflow direction towards the windshield. Using external circulation helps expel the moisture exhaled by passengers from the vehicle, while the outside cold air is less prone to condensation. Important Notes: Note 1: 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 unpleasant odors or fumes, use internal circulation to prevent the poor outside air from entering the car. Note 2: In summer, to quickly cool down the interior with air conditioning, you can use internal circulation. Note 3: In winter, using internal circulation can help keep the interior warmer.
When driving in the rain, I usually keep the air recirculation mode on to block external humidity from entering the car and prevent window fogging, which can obstruct visibility. This is especially important for me since I often drive long distances on highways. During heavy rain, I get nervous about fogging up, but switching to recirculation immediately makes the air feel drier. However, prolonged use can increase carbon dioxide levels inside the car, leading to dizziness, so I briefly switch to fresh air mode for a few minutes every half hour to let in some fresh air. Of course, remember to turn on the defogging function of the AC or simply set it to cooling mode, which works even better. During heavy rain, I also use the windshield wipers—just make sure they’re clean, or they’ll affect visibility. Safety always comes first, so test what works best for your car and driving conditions.
