Why My Car Windshield Fogs Up? 7 Ways to Solve IT

Why My Car Windshield Fogs Up

Fogging up windshields is a normal occurrence in a driver’s life. It is normal but not acceptable because foggy windshields can blur vision, and a blurry vision can result in accidents on the road.

So, what do you do when your windshield fogs up while you are driving down the highway? You blast the defroster, and it removes the fog, but for how long? The fog returns again and again! When a car’s windshield fogs up, it can make the driving experience frustrating and dangerous.

So, If you are asking why your car windshield fogs up and how you can prevent it, you are at the right place. Keep reading to discover why your car windshield fogs up in various situations and how you can solve it.

Phenomena and Situations Which Cause a Foggy Windshield

You have seen your car windshield fog up a few minutes after jumping into the car. There can be various phenomena and situations in which your car’s windshield can fog up.

Car Windshield Fogs Up

It is very common for windshields and windows to fog up when it is snowing. If you think that it fogs up in cold weather, you should know that there are many recorded incidents when the windshield fogged up in hot and humid weather.

One can also face the problem of foggy windshields after washing the car or during rain. While sometimes you turn on the car defroster to remove the fog from the windshield, at other times, you might get foggy windows after you turn on the defroster or heater. In some cases, you might observe fogging of the windshield at specific hours of the day, such as in the morning or at night.

Are you also stuck in one of the situations mentioned above? Take a few moments to read this article to learn what’s causing your foggy windshield and what you can do about it.

Reasons why car windshield fogs up?

If you want to understand how to keep your vehicle’s windshield and windows from fogging up, you first need to understand why they fog up.

Car Windshield Fogs Up Rrimary Reason:

Car windshield primarily fogs up due to the build-up of Humidity or moisture inside the vehicle. Foggy Windshields mostly occur when the Air Conditioner is set to recirculate mode.

Condensation forms on the inside or outside of your car windshield because of the difference in temperature and humidity inside the car and outside it.

Window fog is common inside your car during the winter. This is because your vehicle’s temperature and humidity levels are higher than outside. When the hot vapor from the passengers’ breath hits the cool glass, it condenses on the inside of the windshield.

Fogginess usually occurs on the outside of the car windshield in the summer. This is because the temperature and humidity outside your car are higher than on the inside, where the cold, dry AC is running.

Window fog

So, it is clear that out of many reasons, humidity is the main culprit for creating foggy windshields. You can easily check the humidity level of your vehicle by simply Installing a humidity gauge in the car. The gauge will help you to compare the humidity inside the cabin to the outside humidity. You should keep in mind that the interior humidity level should match the exterior. Even if it does not match, the interior humidity level should not be significantly higher or lower than the outside.

Car Windshield Fogs Up Reason 2:

If your car is new and still has that new car smell, it is because of the VOCs (Volatile Organic Compound). VOCs might still be letting out gases that can put a minor film on the windshield and windows, which increases the possibility of fogging the windshield.

Car Windshield Fogs Up Reason 3:

Another reason that could increase the humidity in the cabin and fog up the car windshield is a moisture leak. All the places might seem dry at first glance, but you should check thoroughly. According to the experts, these are the most common moisture entry points:

  1. There is a high possibility that the moisture is entering the car through the door vapor barrier. You should check if water is present in the door jam (especially the rear doors) after a car wash or rain.
  2. The carpets might be wet. If they feel dry to you, you should remove the rear floor mats and velcro discs. To check for the presence of water, stick a q-tip down in the holes.
  3. Check if the sunroof drain is clogged. To check the clogging, pour water over the closed sunroof and check for any water leaking from the car’s bottom. If there is no water, you need to get it repaired because you may have a clog.
  4. The windshield wiper cowl keeps road debris and moisture out of the windshield wiper system and cabin air filter. Check if it is cracked because it could be the cause of the problem.
  5. You should check the cabin air filter box because water could leak into the car and soak the carpets if the cover is not properly sealed or if something is wrong.
  6. A clogged or dirty windshield is also a possibility. It is advised that you check it, and if it is the problem, you should clean it with isopropyl alcohol.

How to Prevent Windows From Misting Up

It is rightly said that “prevention is better than cure.” So, here are some ways in which you can prevent your windshields from fogging up.

  • Clean your car: Dirt pockets on your windshield are like an invitation to fog. So grab some microfibre cloth and window cleaner and get rid of all the dirt to reduce the chances of fogging on your car’s glass.
  • Park in Garage: As you are already aware now, one of the major reasons for fog on the windshield is the difference in temperature inside and outside your car. So it is wise not to let your car reach below freezing point. You can park your car in the garage at night to keep it warm. This way, you will be ready to move as soon as you hop in the car.
  • Remove any wet items: Because water particles in the air form condensation, removing any unnecessary liquid from the vehicle is wise. Avoid leaving umbrellas, wet coats, or drinks in the car because they will only increase the moisture in the air, and, as a result, you will have a foggy windshield.
  • Shaving cream: This is the first of our odd hacks, but cleaning your screen with shaving reduces condensation. Ice hockey players use shaving cream to keep their masks from fogging up by adding a temporary barrier to prevent water droplets from forming. Simply apply the cream with a microfiber cloth and wipe it away with a clean cloth to prevent smudges.
  • Car moisture absorber: Fill a couple of tights with cat litter and store them in your car to absorb excess moisture. Believe us on this one; it works well. The most direct and convenient way is to buy some car moisture absorber and put it on the car, it will silently work for you to solve the humidity problem for you, no matter in day or night. You will love them.
Why My Car Windshield Fogs Up

Solution: How to Fix a Foggy Windshield?

So, let’s say you were unable to prevent the fogginess; what are you going to do now? You don’t need to worry because you will get to know every possible solution here. You basically have to match your car’s interior temperature to the outside temperature and keep your car dry. If your car windshield fogs up, you could use various methods to solve this problem.

Use a Dehumidifier to Fix a Foggy Windshield:

As you have already learned, car windshield fogs up mainly because of humidity or moisture. One of the best ways to deal with humidity is to use a dehumidifier for your car or dehumidifier for RV. Some companies sell dehumidifiers that your car’s 12V power outlet can power.

Use a Dehumidifier to Fix a Foggy Windshield

However, if you want a less expensive method, you can keep a pack of silica balls on the dashboard of your car. It will absorb all the moisture from the car’s interiors. Keep an eye on the level of wetness in this pack to determine when it’s time to replace it.

Use an Ammonia-Based Window Cleaner to Fix a Foggy Windshield:

You can remove dirt buildup inside your windshield with an ammonia-based window cleaner. Apply the window cleaner with horizontal or vertical strokes. Keep in mind that cleaning it once is not a permanent solution. So, to keep your car windshield fog-free, you need to reapply it to the interior of your windshield on a regular basis.

Using the defrost vent to Fix a Foggy Windshield:

Using the defrost vent to Fix a Foggy Windshield

Using the defrost vent is also a very effective method to get rid of fog on your windshield. Use the defrost vent with the cool air setting turned on. When the defrost vent directs cool air at the windshield, it can help equalize the windshield’s temperature with the outside temperature and defog the car glass.

Using a dishwasher to Fix a Foggy Windshield:

Sometimes, the car windshield fogs up when the weather gets a little bit warmer. In that case, you can use any dishwasher like “Dawn” to clean your windshield. Take part water and part dishwasher on a microfiber towel and clean your windshield with it. Afterward, take a dry towel and clean the glass to remove any smudge.

Using a dishwasher to Fix a Foggy Windshield

Recirculate the air to Fix a Foggy Windshield:

This is an extremely useful tip during the winter. Every car has the capability of either recirculating the air that is already inside or continuously drawing fresh air from the outside for the AC vents. Allowing outside air into the vehicle helps to balance the temperature and reduces fogging on the windshield.

Recirculate the air to Fix a Foggy Windshield

So make sure that the system is not stuck in the recirculation mode. In Addition to defogging the windshield, there are other benefits of drawing the air from the outside. Our cars are airtight, and if we don’t get fresh air for a long time, we start to feel drowsy, which is very dangerous when you are driving.

Control the temperature to Fix a Foggy Windshield:

During the monsoon season, cold rainwater hits your windshield and chills it. On the other hand, the temperature inside the car may be warm, causing condensation on the inner surface and fogging up the windshield.

Control the temperature to Fix a Foggy Windshield

You can set your car’s air conditioning to a colder temperature to match the outside temperature. This will clear the fog and is one of the best ways to defog a car.

Open Lower the Window to Fix a Foggy Windshield:

Open Lower the Window to Fix a Foggy Windshield

This method is useless during rain, but other than that opening the window a little is very effective. When outside air suddenly fills your car’s interiors, the temperature inside begins to match the temperature outside, reducing windshield fogging.


When you are driving on the road, whether it is winter, summer or monsoon, visibility should be the number one priority. Lack of visibility causes a lot of accidents every year, and fogging up windshields is one of the major causes of that. These tips and tricks are extremely effective and helpful. Taking precautions will not only keep you safe, but it will also ensure the safety of others. So, the next time you run into a similar situation, you don’t have to compromise your safety because now you know what to do.

Mohd Aqsat

Hi there, My name is Aqsat and I was born and raised in Delhi in India, and I have a degree in English from Amity University. I have acquired knowledge in various fields, such as education and e-learning, environment, health and care, finance, digital marketing etc. I have had the pleasure of working with a variety of home experts in my career. I have spent time helping these experts to build their businesses while assisting homeowners in caring for their greatest asset. I have been involved with indoor and vehicle air quality for a long time and feel that poor indoor air quality is one of the major problems. Now I have gotten the opportunity to share what I have learned. I hope you will find the content helpful.

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