How to defog windscreen glass fast

Key Takeaways:

We’ve all been there. You’re already running late, you jump in the car on a cold morning, and you can’t see a thing through a misted-up windscreen. The good news is it’s a quick fix once you know how, and knowing how to demist car windscreen glass safely makes those winter starts far less stressful, and a lot safer too.

In this guide, we’ll explain why your windscreen gets foggy, how to defog windscreen glass fast, and what you can do to stop the fog popping up again.

Why do car windows fog up in winter?

Fog forms when warm, moist air meets a cooler surface. In winter, the air inside your car is usually warmer and more humid than the cold glass, thanks to your breath, damp clothes, wet shoes, and a bit of leftover rain. When that warm air touches the cool windscreen, the moisture turns into the thin layer of fog you see.

It comes down to a simple bit of science: warm air holds more moisture than cold air. The bigger the temperature gap between the inside of your car and the glass, the more likely you are to get windscreen fog. It’s completely normal and easy to sort out.

Tips to defog your car

The good news is that clearing a foggy windscreen is usually quick once you know which buttons to press. Knowing how to remove fog from car windscreen glass in winter is mostly about balancing temperature and moisture, warming the glass while drying out the air inside the cabin. Here’s how to get it clear and keep it that way.

How to get rid of fog on windshield glass

If your windscreen has fogged up on the inside, work through these steps:

A foggy windscreen inside is by far the most common in an Aussie winter, so most of the time your demister and air con will do the trick.

But why does my windscreen fog up on the outside sometimes, too? In warmer, humid weather, the opposite happens: your air con cools the glass below the temperature of the muggy outside air, so the condensation forms on the outside instead. A quick flick of the wipers clears it, and nudging your cabin temperature up a little stops it coming back.

How to defog car windows

The same approach works for your side and rear windows. Most cars have a separate rear demister button, marked with a little symbol of a window with squiggly lines. It heats the rear glass directly to clear it. For your side windows, aiming some airflow towards them and keeping the cabin air dry will clear them in a minute or two. Wiping the glass with a clean microfibre cloth can help in a pinch, but try not to smear it, as leftover residue can create a ‘haze’ effect even when the fog is gone, impacting visibility.

How to stop windscreen fogging up?

Clearing fog is one thing; stopping it coming back is even better. To help stop windscreen fogging in the first place:

And if it keeps fogging up no matter what you try, your local mycar team is happy to take a look.

What if my car doesn't have air con or a demister?

Not every car has one-touch demisting or air conditioning, and that’s perfectly fine; you can still clear a foggy windscreen, it just takes a little longer. Older cars rely on warming the glass and swapping the damp cabin air for drier outside air, rather than drying it with your air con.

If your car has manual heating and ventilation controls, try this:

Without air con you can’t actively dry the air, so the heater needs a little time to warm up first. On very cold mornings, give yourself an extra minute or two before setting off rather than driving with limited vision. Your safety comes first.

No heated rear window? Wipe it with a microfibre cloth or crack a rear window to keep the air moving. A little anti-fog product on the inside of the glass, plus a moisture absorber like a silica gel pack, also helps older cars that fog up easily.

When to get your windscreen checked

Sometimes fog, damp, or moisture that just won’t shift can point to something bigger, like a worn seal or a small leak letting water in. Chips and cracks can trap moisture too, and tend to worsen over time in cold weather. There’s no need to worry, though. If your windscreen needs more than a quick demist, the team at mycar can help. Take a look at our windscreen repairs, and we’ll make sure your seals and glass are in good shape for the season ahead. With 275-plus stores around the country, there’s a good chance there’s one near you.

Ready for clearer mornings?

A foggy windscreen doesn’t have to slow down your day. With the right use of your demister and air con, plus a few habits to keep your car dry, you can clear the glass fast and keep it that way all winter, with the peace of mind of seeing the road clearly.

Need a hand keeping your car winter-ready? You can find your nearest mycar store or call the team on 13 13 28. Want more cold-weather tips? Head to our News & Car Advice blog for more practical advice for Aussie drivers. That’s care beyond the car.

Brought to you by the expert team at mycar, one of Australia’s largest tyre, servicing and repair networks, with 275-plus stores nationwide. We keep up with the latest in vehicle tech to give Aussie drivers clear, practical advice and to help keep your car safe and reliable on the road.