How to defog your windshield: A quick guide

August 24th, 2022 by

No matter what time of year it is in Florida, it seems like foggy windshields are consistently a thing. Summer or winter, you can pretty much count on having to use your wipers or defroster to get a clear field of vision before you leave the house. But why do windshields and windows fog in the first place, and how can you effectively get them clear again? Check out Toyota of Orlando’s guide on how to defog your windshield before you hit the road.

how to defog windshield

How to defog a windshield: Why does it fog in the first place?

First, let’s talk about why foggy windshields and windows happen in the first place. It all boils down to moisture either inside or outside of the car and temperature. Here’s the breakdown:

  • When it’s hot and humid outside (so like 70% of the year in Orlando), there’s a lot of moisture outside of the car in the surrounding air. When this moisture hits the cool glass of your windshield and windows – especially if you have the A/C going – the temperature there causes fog to form on the glass. This temperature at which the fog forms is called the dew point. Driving in the rain can also lead to a foggy windshield.
  • When it’s cold outside, the moisture inside of your car – from your breath, humid air trapped inside the cabin, wet shoes, etc. – touches the windshield (which is chilled from the cold temps outside) and hits the dew point, causing fog to form.

Foggy windshields and windows are dangerous because they impede you from being able to see clearly outside of your car, which can lead to a car accident or collision. That’s why it’s important to get rid of the fog before you leave the driveway.

Toyota of Orlando explains how to defog a windshield

So how do you do it? It depends on the temperature outside and why fog is forming. Here’s our quick guide on how to defog a windshield.

  • If it’s cold outside, the fog is forming on the INSIDE of your glass (remember, it’s from the moisture inside the car). This means you’ll need to use your car’s defroster/heat/AC to dry things out inside the car and clear your windshield and back window.
    • First, crank the heat and turn on your defroster. This will temporarily clear things up, but the goal is to get the moisture out of the car to prevent any more fog from forming.
    • Next, turn on the A/C (cold air will help to pull out the moisture from the car).
    • You should also turn off your recirculating feature so your car doesn’t continue to circulate humid air through the car and instead, pulls in fresh, cold air from the outside.
    • Finally, open your windows to let the humidity out of your car and to let more cold air from the outside in.
  • If it’s hot outside, the fog is on the outside of the glass (because the moisture is outside of the car). This one is an easy fix – turn your wipers on and roll your windows down and back up again to clear the fog away from the glass. You can also turn down your A/C to clear the glass faster.

And luckily, there are ways to prevent fog from happening in the first place. Here are some quick Orlando Toyota tips:

  • Keep your car clean. Moisture is more likely to stick to dirt, so clean the inside and outside of your windshield routinely.
  • If it’s cold outside, wipe your shoes off before you get in the car to remove some of the moisture.
  • Use a defogging solution on the glass – our Orlando Toyota parts store can help you find the right products. You’ll want one formulated for the interior and one formulated for the exterior, and be sure that it won’t affect any tint that you have on the windshield.
  • Try a home remedy. Some drivers swear by shaving cream; apparently, applying it to the glass on the interior of your windshield and then wiping it away will help prevent the glass from fogging.
  • Stay on top of routine service for your air-conditioning system and let our Toyota of Orlando techs do maintenance and repairs as necessary.

Have questions or need to find defogging products? Toyota of Orlando is here to help. Call us at (407) 298-0001 or stop by our Service and Parts Center here in Orlando at 3575 Vineland Road, just off I-4 near the Millenia Mall.