Quick and Easy Steps: How to Defog Your Windshield

November 16, 2023
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A foggy windshield isn’t just annoying—it’s dangerous, too. Understanding how to defog your windshield can make your drive safer and more comfortable.

There are two main methods to clear a foggy windshield. For cold weather, turn off recirculation, turn the heat to max, switch to AC, and then crack a window. In humid weather, turn the AC off, turn the defog on, and turn on your wipers. If fog persists, then use an anti-fog spray.

Let’s examine both methods and see if they’ll work for you. 

Why is My Windshield Fogging Up?

Why is your windshield fogging up? Understanding the reasons behind this frequent issue offers crucial insights for prevention.

The fog formula

An increase or decrease in temperature mixed with the moisture content in the air creates fog.

In other words, hot air holds moisture (humidity) while cold air does not. That difference in air temperature on the outside of the car versus the inside manifests as fog. 

How to Get Rid of Fog on Windshield When it’s Cold Outside

  • Start by turning off recirculation and turning on defrost/defog.
    • Recirculation recycles the air in the cabin which is an excellent way to prevent outside air pollutants or smells from entering the vehicle.  
    • When recirculation is off the car’s cooling system filters new air from outside, disrupting the moisture level within the cabin. 
    • The recirculation button looks like the outline of a car with an arrow in the center.
  • Turn the heat on the highest setting and blast it.
    • Moisture content rises in the air.
  • Next, turn on the AC at the highest setting.
    • The cold air pulls all of that moisture from the air. 
  • Briefly, crack a window for the air exchange. 

How to Get Rid of Fog on Windshield when it’s Hot Outside

Condensation on the windshield’s outside indicates it’s hotter outside the vehicle than inside. 

  • Turn on your wipers to clear away the moisture for better visibility. 
  • Please turn off the AC or lower it so that the air inside the cabin is closer to the temperature outside. 
  • Once the car has warmed, turn off recirculation.
  • Turn back on the AC.
    • You can have the AC on now since the temperature in the car has equalized. 

How to Get Rid of Fog on Windshield When Raining 

How to defog your windshield when it’s raining is similar to when it’s hot and cold. First, determine the temperature outside – is it a humid rainstorm or an icy storm? Depending on the answer, you will utilize a mixture of the abovementioned steps.

If it rains more in your area, consider a window cleaner with defogging properties to save you from a headache. 

How to Defrost a Windshield Without Heat

No heater? No problem. Learning how to defrost a windshield without heat is straightforward. 

  1. Use a plastic scraper to clear ice from the windshield. 
  2. Douse the glass with a de-icing agent.
    1. A homemade solution includes three parts: water, isopropyl, and vinegar. 
  3. Turn on your wipers to clear away the remnants. 

Do not put hot water on the windshield glass or it will crack. The abrupt temperature change might even cause it to shatter completely.

Other Alternatives to Defog Your Windshield

Here are some quick alternatives to avoid the procedures already mentioned. As a part of your car’s regular maintenance you can clean the windshield with these:

  • Anti-fog spray or solution.
    • Store-bought or homemade, spray this on the outside and inside of the windshield.
  • Shaving cream.
    • Slather this on the inside of the windshield and then wipe it off. 
  • Anti-fog windshield films.
    • This is an easily applied adhesive window film.

For best results, continue to replace these solutions as needed.

Need Help?

If it’s nicked or cracking, your windshield glass might have more significant issues than fog. Kryger Glass is home to a team of highly qualified auto glass technicians ready to restore your windshield today. We have locations available in Iowa, Kansas, Missouri, and Nebraska. Look for a Kryger Glass branch nearby and contact us for more information on windshield replacement, repair, and maintenance.

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