Why Does My Windshield Keep Fogging Up?

Foggy windshield with rain on it. Tom's Automotive Service

This is such a great question for our West Seattle dwellers and drivers (and the rest of the Pacific Northwest too).


Foggy windshields are all about moisture content, cold temperatures (specifically those below the “dew point”*). 

Your AC Plays a Role

It’s true. The air conditioner in your vehicle helps to draw out and dry out the moisture in the air. It’s actually tied in to your defroster unit in your car, truck, SUV, or hybrid. This is why we may check in on your AC to make sure it’s functioning properly during the wet, ice, and snow times of the year.

Lots of rain, fog, the occasional snow-and-ice showing happen right here and contribute to foggy windshields throughout the city.

It’s important to be able to quickly clear your windshields before you get out on the roads. Visibility is something you want to maximize at all times to keep yourself and those in (and out) of your vehicle safe.

Fog Prevention

  1. Clean the inside of the windshield: dirt, dust, and debris on a windshield can hold moisture, so when there isn’t any, there’s nothing for the moisture to be absorbed by.
  1. Year-round swimming? If you’re taking cold polar-dips in the sea or keeping up a swim routine, be sure to remove all wet towels and gear from the vehicle, as these add to the moisture level inside.
  1. Roll’em up: Keep your passenger windows rolled up to keep out additional drips and drops. 
  1. Clear ‘em out: Get all of the leftover drinks with open tops out of your vehicle when you leave. 
  1. A word about products: There are definitely products available for sale to help with clear windshields. The thing is, re-application is necessary when you begin using them. There is no one-and-done product that will take care of keeping your windshield clear forever. 

Especially here in West Seattle.

Keep breathing, but just know…

Condensation and moisture come from our breath and breathing too. Crack your windows, have a dry microfiber towel or chamois handy, be sure your defroster is in good working order and turn it on and up to dry out your foggy windshield.

So, while it’s inconvenient and not fun to wait for the windshield to clear as the vehicle warms up and the defroster, which activates part of your air conditioner, gets going, it’s still important. Critical, actually. 

Get where you need to go safely. All day. Everyday.

If you’re wondering whether or not your defroster, air conditioning (AC), and heater are working as efficiently as they can, we’d love to take a look. Schedule your service appointment with us now.

*Dew Point: The temperature at which dew forms.