Knowing a Little Science Can Help De-fog Your Windshield in Minutes

Written by Mary Wasson, Meteorologist

Last updated 1/26/2024, 10:40:30 PM

Foggy windshields are common occurrences in the morning, especially in the winter. This could cause a wrinkle in your morning routine as it takes time to de-fog your windshield and adds time to your commute.

Did you know that the temperature and moisture difference between the inside and outside of your car is to blame? The warm, moist air inside encounters the colder surface on the windshield, causing condensation and fogging up your windows. Much like when you try and “fog” up a mirror or window with your breath.

Science states that hot and dry air can hold more water than cold air, so the fastest way to defrost your windshield is to make the air around it as hot and dry as possible.

According to and YouTuber Mark Rober, former NASA employee, and Mechanical Engineer, he breaks down how to defog your windows quickly by following these steps:

-  Turn the heater on to its highest setting.

-  Turn on the air conditioning

-  Make sure air recirculation is off

-  Then roll down your window for a few minutes

Some other things to try are to wipe down the inside of your windows with an anti-fog solution or shaving cream, keep a microfiber towel handy to remove condensation, and fill a sock up with cat litter and place it on your dashboard next to your foggy window.