Windshield Fogging Up? Here’s Why!

3 MIN READ | JANUARY 21, 2022

It happens to all of us. We get into our car and drive off –  after a few minutes, the windshield is foggy, making it a challenge to see where you’re going. First and foremost, if your windshield gets extremely foggy and it’s taking quite some time to clear, it’s best to pull over for your safety and resume driving once the fog is gone. 

If you’re wondering why your windshield is fogging up, you’ve come to the right place. Below are a few different reasons for why there’s fog on your windshield and auto glass and how to clear it up quickly. 

If you notice other issues with your windshield, such as water leaking around the edges, rattling noises, or a draft when driving at a high speed, give us a call right away for windshield repair and replacement services. There may an issue with the windshield or a sign of defective glass.

Reasons your windshield is fogging up

• Condensation – Moist, warm air condenses when it hits your car’s colder windshield, which usually happens in the early morning. This occurs because these conditions cause relative humidity and when the temperature decreases more, the water needs to find its way out. A cool morning with warm air condensation results in your windshield fogging, an occurrence that is more common for areas with quick and frequent weather changes like Calgary.
• Humidity – In a dry climate like Calgary, you wouldn’t expect humidity to be a reason for your windshield fogging up. However, if you notice your windshield and auto glass fogging up when there are multiple people in the car, humidity plays a factor as it can cause water to convert into vapour quickly.
• Heat – Windshield fog doesn’t just happen during cool mornings. If your car is left in the sun, it will of course heat up faster than if it were in the shade. The glass will heat up and cool down much faster than the air inside, so when you get into the car, there are pockets of warm air that are trapped next to the windows, which are not heated or cooled yet. This causes fogging.

How to quickly clear away fog on your windshield 

There are a few simple steps you can take to defog your windshield:

• Run the air conditioner, which works best when the outside temperatures are above freezing and damp.
• You can run the heater at the lowest setting or run it through your defrosters, which causes the condensation to evaporate. This is ideal if you can catch the fog buildup early.
• Based on your comfort level and the temperature outside, open your windows to let cool air in. This method is especially beneficial if there is an issue with your vehicle’s HVAC system that makes it difficult to defog your windshield.

Whether you’re running the air conditioner or the heater, be sure to turn off the recirculation feature to pull in the outdoor air.

If you suspect that there is an issue with your windshield itself, don’t wait to get it serviced. Remember, your windshield is an essential component and a critical safety feature on your vehicle. Call us today with any questions and we’ll be happy to help!