How to Prevent your Vehicle from Fogging Up


Foggy windows are a pest, especially in wintertime. But it’s not just annoying – foggy windows interfere with your vision, making you an unsafe driver. This can result in a ticket, or worse, an accident! So how do you prevent foggy windows? Can you fix windows that are fogging up?


How to Prevent your Vehicle from Fogging Up At Lancaster Toyota in East Petersburg, PA | Woman with black hair driving her car with both hands on the steering wheel
What Causes Car Windows to Fog?/

The fog on your windshield, back window, and side windows is condensation that forms when there is a difference in temperature and humidity close to the glass. However, depending on the time of year, where the fog occurs and how it occurs will differ. This is dependent on where the warmer, moister air is present.

In the summer, condensation generally occurs on the outside of the glass. You’re running the air conditioning, blowing cold dry air onto the windshield. Outside, the hot moist air is coming into contact with the chilled air contacting the bottom of the windshield inside.

The opposite occurs in the wintertime. The cold, dry air is outside of the vehicle. Meanwhile, inside the car, you’re trying to make sure you stay warm – which includes heated air coming into contact with the windows.

Why Do Windows Fog More in the Winter and in Wet Weather?/

Condensation is the same thing that lets you see your breath in winter. You’re breathing the same in winter and summer – but you don’t see your breath often if ever in the summer, do you?

In the winter, when you’re seeing condensation inside the vehicle, it’s because the moisture is in a smaller, more contained space. In the summer, the moisture and warmth are outside, so you just get spotty fogging. In the winter, as you try and keep the inside of your car warm and toasty while breathing and sipping coffee, the moisture is all trapped there. This means all the windows will fog, not just the spots around the vents.

A cold rain on a vehicle with a warm interior – particularly in the summertime – will have the same effect, and will also cause fogging. As you try and keep the interior pleasant, being surrounded by moisture will make all glass surfaces more prone to fogging.


How Do I Prevent Car Windows from Fogging?/

There’s really no “best way” to get rid of foggy car windows. What works best for your vehicles will often depend on the source of the fogging and moisture – try these solutions until you find the one that does the best for you!

  • Switch Off Recirculate: If you need to clear that fog right away, make sure to switch off the recirculate function. This will cause your system to pull in drier outside air, instead of trying to pull moisture out of your interior air as it recirculates.
  • Hot Air + Air Conditioning: This one sounds a little weird, but it works! The air conditioner will dehumidify while the hot air will help to warm up the interior. Check out a great explanation of this method!
  • Clean Your Windows and Car: Dirt traps moisture and heat. On top of that, if you’re leaving wet clothing and open containers in your vehicle, you’re introducing more moisture. Clean your windows, and dispose of anything that may be holding excess moisture that can make its way into the air in your vehicle’s interior.
  • Anti-Fogging Spray: Easy to find at your closest auto shop, big box warehouse, and even supermarkets, anti-fog spray is pretty clear what it does. Simply follow the direction and you should be good, although you may have to treat your windshield or windows often.
  • Silica Car Dehumidifier: It’s the same stuff that keeps moisture out of clothing – use silica car dehumidifiers to absorb moisture in your vehicle! These can be in bags or sacks, or in containers where the silica can be changed out. You could even use the little bags that come in shoes or clothing – but they won’t do all that much. We suggest checking out the different options for car dehumidifiers to see what works best for your vehicle.
  • DIY Ideas: There are other ways that we don’t necessarily back, but others have found to help. One is to rub shaving cream on the windshield and windows. Another echoes the previous tip, using an athletic sock full of silica-based cat litter. These may work as quick, DIY fixes but you’ll be better served in the long run using the tried-and-tested suggestions.
    • How to Prevent your Vehicle from Fogging Up At Lancaster Toyota in East Petersburg, PA | Man in grey jacket is using an orange windshield cleaner to get the ice off of his car windshield

    Preventing Recurrences/

    Now that you’ve treated your vehicle, you don’t want it coming back. Avoid bringing more moisture into your vehicle in the future by

  • Bagging wet clothing in the winter instead of letting the moisture seep into the seats
  • Knocking snow and ice off your clothing before getting in the vehicle
  • Not allowing liquid containers to accumulate
  • Cleaning up and wicking out any moisture the moment it is spilled or collects.

    • Fog on your windshield and windows is dangerous – don’t drive when your visibility is reduced by it! Make sure to treat your foggy windows and prevent them from getting foggy in the future using the methods we’ve recommended – or let us know if you’ve found an even better way!

    And, If you are looking for a new or used vehicle contact us at Lancaster Toyota, or take a look at our inventory online.