When fog appears on your car windows, it’s not only frustrating but also dangerously inhibits your visibility. Fog can occur at any time of the year, and you don’t have to be a meteorologist to understand how fog works in order to prevent it. We’ve done the research for you, to explain how to keep your car windows from fogging.
Keep the air temperature and humidity on the inside of your car as similar as possible to the air temperature and humidity outside, and fog will less likely occur.
Of course, you and your passengers don’t want to ride uncomfortably in a freezing cold or stifling hot car. Keep reading, and we’ll discuss how you can adjust your car’s interior climate during warm or cool weather in order to prevent fog from appearing on your car’s windows.
And if your windshield has a persistent blur but it’s not fog, we’ll also discuss how to best clean off the grime on the windshield for optimal visibility.
Why Do My Car Windows Keep Fogging Up On The Inside?
Fog occurs with the right conditions of air temperature and moisture content in the air. When the air temperature drops below a specific temperature, called the dew point, the air can no longer hold any moisture. At the dew point, any water vapor in the air condenses, or turns into droplets, creating a fog.
When it’s cold outside, you turn up the heat in your car. The inside temperature warms the glass to become higher than the dew point. When the cool outside air hits the warm glass, any excess moisture in the air on the inside of the car condenses to form tiny water droplets on the inside of the glass. Excess moisture in the air inside the car could come from passengers exhaling, a wet umbrella or wet snow on the floor.
To keep your windows from fogging on the inside:
- Turn down the heat. If the inside air temperature and outside air temperature are similar, there is less chance of condensation occurring. Adjust the heat to as low a setting as comfortable.
- Run the fans on high. Turning on the fans will help to cool the inside air faster.
- Turn OFF the recirculate air feature so the heating/cooling system will draw outside air into the car. This will help to regulate both the inside air temperature and moisture level to more closely match the outside climate.
- Turn ON the defrost feature using cool air. The cool air will blow directly against the windshield glass to help to regulate the temperature between the inside and outside air against the glass.
- Open a window to quickly cool the inside air temperature and release moisture.
Keep a clean, soft cloth handy just in case the windshield or windows fog so quickly that you have to wipe away the water droplets in order to maintain clear vision as you drive.
How Do I Stop My Windshield From Fogging During Winter?
Removing ice and snow from the windshield before you get inside the car can stop the windshield from fogging as you drive. For quick removal, turn on your car and adjust the defrost feature to run on high using cool air. Let the car run for a short time before you start scraping. The warm engine and air from the defroster (slightly warmer than outside air) will loosen the ice and snow.
DO NOT:
- Pour hot water onto the windshield - this could crack the glass.
- Turn on the windshield wipers until all the ice and snow have been removed - this could damage the wiper blades.
De-Ice With Ease
Remove ice and snow even faster by spraying de-icer on the windshield before you start to scrape. These products are specially formulated to melt ice without risking a cracked windshield.
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Stay Warm Inside - Not Too Hot
From inside the car during winter you can stop fog by keeping the heat low, running the defrost feature using cool air, and turning OFF the recirculate air feature - as we’ve previously discussed.
How Do I Stop My Windshield From Fogging When It Rains?
When it’s raining, you might not be as inclined to open a window in order to equalize the temperature between the air inside your car and the air outside. But, you can still try to lower the inside air temperature as quickly as possible by:
- Lower the heat.
- Run the fans on high.
- Run the defrost feature on high using cool air.
- Turn OFF the recirculate air feature.
If your climate is prone to rain, Hyundai recommends applying a specially formulated glass cleaner on the outside of your windshield to repel raindrops. So, while you are mitigating fog from the inside, you won’t struggle to see clearly through the rain falling on the outside.
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How Do I Defog My Windshield In Summer From Humidity?
During warm weather, fog forms on the outside of your windshield because the outside air temperature is higher than the dew point of the inside, air-conditioned glass. When the warm outside air hits the cool glass, excess moisture in the outside air - or humidity - is released and condenses on the outside of the glass.
You can defog your windshield in the summer by:
- Turning on the windshield wipers to wipe off the water droplets that have condensed on the windshield.
- Adjusting the AC to the least-cool temperature, without getting too uncomfortable, or turn off the AC completely.
- Turn OFF the recirculate air feature so the heating/cooling system will draw outside air into the car. This will help to regulate both the inside air temperature and moisture level to more closely match the outside climate.
- Open your windows to rapidly equalize the inside and outside air temperatures and moisture levels.
How Do I Clean A Blurry Windshield?
Driving with a blurry windshield is hazardous to you and other drivers because your visibility is limited. Try to clean the exterior of the windshield while you drive by using the washer feature on your windshield wiper lever.
If the wipers and washer fluid do not remove the blur, you’ll want to thoroughly clean the interior and exterior of your windshield as soon as possible to remove any grease, bugs, and dirt. When the car is safely parked, clean the windshield by following these simple steps:
Exterior
- Lift the windshield wipers.
- Spray the windshield’s exterior surface with glass cleaner.
- Wipe with straight, back-and-forth motions using a microfiber cloth.
- Buff the windshield’s exterior surface by using a dry, microfiber cloth moving in a tight, circular motion.
- Lower the windshield wipers.
Interior
- Remove any personal items or trash from the dashboard and cover the dashboard with a clean, soft cloth to protect it from falling dust or debris.
- Spray the windshield’s interior surface with glass cleaner.
- Wipe with straight, back-and-forth motions using a microfiber cloth.
- Buff the windshield’s interior surface by using a dry, microfiber cloth moving in tight, circular motions.
- Take-up the cloth from the dashboard and reassemble your belongings.
Avoid cleaning your car’s windshield in direct sunlight as it causes the glass cleaner to evaporate quickly and could leave behind grime and streak the glass.
What Is The Best Product For Cleaning The Inside Of Car Windows?
We recommend these automotive glass cleaners for cleaning the inside of your car windows, products that are highly rated by automotive detailers.
A high-performance cleaner, Invisible Glass will remove stuck-on debris and grease to leave a streak-free shine. Safely use on tinted windows.
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Meguiar’s tough-acting formula removes grime and bug residue leaving behind a streak-free, dust-resistant finish. It is safe to use on tinted windows.
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Professional-grade cleaner, Chemical Guys does the trick to remove grime in one swipe. Safe to use on tinted glass.
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Drive safely, with optimal visibility when you adjust your car’s climate to prevent foggy windows. If you’re steering clear of fog, don’t forget to keep your windshield clean for a clear view of the roadways.