Nothing can be more frustrating for a driver than struggling to clear a windshield that keeps fogging up in the winter. We’ll explain why this happens.

Windshield Fogs Up During The Summer 1 4 Reasons Why Your Windshield Fogs Up During The Summer (Explained!)

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Why does my car’s windshield get foggy in the summer? 

The windshield fogs up in the summer because of an increased humidity level inside the car. This happens because of heavy breathing, poor airflow, too much cold air from the AC, rainy weather, and moisture sources. The best way to stop fogging is to open the windows or use the defrost setting. 

Most people don’t realize that windows and windshields still fog up in the summer because of the increased humidity in the air. We have done the proper research and tested different techniques to figure out why this happens and how to fix it below. 

Summer Windshield Fog Explained

When the summer rolls around, more people notice that their windshields are fogging up. This can be a major inconvenience for drivers. Here’s why it happens and what drivers can do to prevent it from happening again.

The most common reason for windshield fogging is the humidity in the air. When the car heats up from the inside, it evaporates moisture from the air and onto the windshield or windows. 

Humidity is the primary reason this happens, so it’s best to try and keep these levels low. This can be done using the defog or defrost setting in the car. 

The windshield may fog up in the summer because of heavy breathing in the car and too much cold air from the AC. Windshields also fog up more in the summer on rainy days because of increased humidity and a lack of airflow. 

Airflow is necessary to keep the inside and outside temperatures from being too different.

If the inside temperature is higher than the outside temperature, there will be condensation on the windshield, leading to fogging.

High Humidity Levels Inside The Car

Disable Steering Wheel Lock 1 2 4 Reasons Why Your Windshield Fogs Up During The Summer (Explained!)

When the air is humid, it can cause moisture to build up on the windshield. This will reduce visibility and make the car more difficult to drive.

The humidity levels inside the car can also cause the windshield to get foggy during the summer. This is due to condensation caused by high heat and humidity.

There are hacks like shaving cream or potato starch on the windshield to help with humidity. However, we recommend avoiding these hacks, keeping the windshield clean, and focusing on airflow and moisture. 

Heavy Breathing Inside The Car

More breathing happens when multiple passengers are in the car, which releases more air moisture. Without proper airflow, this breathing and moisture can cause the windshield to fog. 

This eventually causes more condensation on the windows, especially when the outdoor temperatures are much warmer.

For example, if the AC is on while passengers breathe heavily, it creates humidity. 

This is why too much AC can cause the windshields to fog up when misused. 

Too Much Cold Air From The AC

Humidity and condensation happen in a car when warm or humid air contacts a cool car window. So humidity can increase when the AC is turned on high, and the car’s interior gets colder. 

This is why excessive use of the AC defogging setting causes the window to fog up and condensation to form. 

When this gets paired with other causes like increased temperatures outside, heavy breathing, moisture sources, and high humidity, the windows get foggy. 

Rainy Weather

Lastly, rainy weather is a common cause of fogging inside cars and on the windshield. This is because the outside temperature becomes colder than expected, and moisture gets trapped in the vehicle. 

Not all cars are good for rain, but understanding how it can cause fogging is a good way to maintain visibility. 

How To Stop A Windshield From Fogging Up In The Summer

Windshields can fog up for several reasons, as discussed. Fortunately, cleaning the windshields from fog is not difficult to improve visibility while driving in the summer. 

These methods include cracking open the windows, turning on the defrost settings, using the recirculate setting in the car, and removing all moisture sources inside the vehicle. 

Crack Open The Windows

This is a very common problem for drivers during the summer because hot temperatures and moist air cause high humidity levels. 

These conditions make it difficult for drivers to see through their windshields, leading to accidents. The fastest way to solve the issue is to open windows for better airflow and to help with humidity inside the car. 

After a few minutes, the windshield should clear up to restore optimal driving visibility. 

Turn On The Defog/Defrost At Medium Temperature

The defog or defrost settings are very helpful when trying to stop the windshield from fogging up in the summer. Turning on these settings will keep the windows and windshield clear, allowing passengers and the driver to see through them better.

The key is to keep the temperature around 68 to 72 degrees, though. When the air is too cold, it only creates more fogging because of the warmer temperatures outside. 

Try Using The Recirculate Setting

The recirculate button is a setting option in most cars that cuts off air from outside of the vehicle. Instead, it uses only air inside the car and recirculates it inside the vehicle. 

This can help with windshield fogging because it decreases humidity and moisture levels in the car. 

Remove Moisture Sources From Inside The Vehicle

When turning on the car to start it up in the summer, it’s possible to notice the windshield is fogging up. This is because of the hot air inside the car that is coming into contact with the cold outside air.

When moisture sources like wet towels, open water bottles, and anything else that might be damp get left in the car, they create condensation. Remove these moisture sources to eliminate the fogging issue. 

Key Takeaways

  • The windshield fogs up in the summer in a car because of humidity levels rising and a lack of airflow inside the car. 
  • Humidity can increase in the car because of heavy breathing, too much cold air from the AC, and rainy weather too. 
  • To stop a windshield from fogging up in the summer, crack open the windows, turn the defog or defrost settings on medium temperature, use the recirculate setting, and remove moisture sources from the car. 

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