How to Stop Your Windscreen Freezing Overnight: 7 Practical Tips

Few things slow down a winter morning like a frozen windscreen. Scraping, waiting for the blowers and wiping away smears can easily take ten minutes, and you cannot legally set off until you can see clearly. The good news is that most of that work can be avoided with a little preparation the evening before.

This guide explains why windscreens frost over, the practical ways to stop it happening, and how to clear the glass safely if you do wake up to ice.

Why does a windscreen freeze overnight?

On a clear, still night, your car's glass loses heat to the open sky. The windscreen can cool below the surrounding air temperature, so moisture in the air condenses on it and freezes into frost, even on nights when the air itself is only just around freezing. Cloud cover, shelter and anything placed between the glass and the sky all reduce that heat loss, which is why the methods below work.

Seven ways to stop your windscreen freezing

1. Use a windscreen frost cover

A cover sits on the outside of the glass, so frost forms on the cover rather than the windscreen. In the morning you lift it off, shake it out and drive away. For most drivers parking outside, it is the simplest way to avoid scraping altogether.

To get the best from a cover:

• Fit it in the evening, before the temperature drops, ideally on dry glass. A cover laid over a wet screen can freeze to it.
• Make sure it is held securely so it cannot lift in the wind. Depending on the design, this may be door flaps, mirror straps or magnets.
• Check the size against your windscreen before buying. A cover made for a large SUV or van will overhang a small hatchback, while a small cover will leave gaps on a bigger vehicle.
• Let it dry before folding it away, and remove it completely before you drive.

2. Park in a garage or a sheltered spot

A garage is the most reliable protection of all. If you do not have one, parking close to your house, under a carport or beside a wall reduces exposure to the open sky and can noticeably cut the amount of frost.

3. Think about which way the car faces

Parking so the windscreen faces east means the morning sun reaches it first, which can help loosen light frost before you leave. It will not help much on a dull or very cold morning, so treat it as a bonus rather than a solution.

4. Try a night-before de-icer or frost-prevention spray

Some de-icers are designed to be sprayed on in the evening to limit frost forming or stop it bonding to the glass. Follow the instructions on the product you choose, and keep a standard de-icer in the car for mornings when frost still appears.

5. Use proper screenwash

Plain water in the washer reservoir can freeze in cold weather, leaving you unable to clear the screen while driving. A winter screenwash mixed to the strength shown on the bottle helps prevent this.

6. Use a dry makeshift cover in an emergency

If you are caught out without a cover, a piece of thick, dry cardboard or an old dry towel held in place by the wipers can do the job for one night. Avoid newspaper or anything damp, as it soaks up moisture and can freeze to the glass.

7. Reduce moisture inside the car

Ice and mist on the inside of the windscreen usually come from damp in the cabin. Shake snow off your shoes and coat before getting in, avoid leaving wet umbrellas or clothing in the car, and keep the inside of the glass clean.

How to clear a frozen windscreen safely

If you do wake up to ice, allow time to clear it properly:

• Start the engine and set the heater to the windscreen with the rear demister on. Stay with the car while it runs; leaving the engine idling unattended is risky and, on a public road, can lead to a fine.
• Use a de-icer and a plastic scraper. Do not use a credit card, metal tools or anything that could scratch the glass.
• Never pour boiling or hot water on the windscreen. The sudden change in temperature can crack the glass, and the water can refreeze on the screen or the ground.
• Do not run the wipers until the ice has gone, as frozen blades can tear or damage the wiper motor.
• Clear every window, the mirrors, the lights and the number plates, and brush snow off the roof so it cannot slide onto the windscreen when you brake.

Rule 229 of the Highway Code says you must be able to see, so all snow and ice must be cleared from your windows before you set off. Driving while peering through a small gap is unsafe and can result in a fine and penalty points.

Windscreen cover or de-icer: which is better?

They do different jobs, so most drivers benefit from having both.

A cover saves the most time if you park outside every night. A de-icer and scraper are still worth keeping in the car for when you are away from home or the cover is drying.

A cover for larger vehicles

If you drive an SUV, van, pick-up or other larger vehicle, our car windscreen snow and frost cover is sized at 157 x 126 cm and is designed to cover the windscreen, wipers and rear-view mirrors. It is made from a five-layer construction with a double-sided aluminium coating and has stitched-in magnets to help hold it in place. As with any cover, measure your windscreen first to check it suits your vehicle.

You can find it alongside gloves, thermal socks and other cold-weather pieces in our winter collection. We offer free standard delivery to the UK and US, with an estimated delivery time of 5–8 business days, or fast delivery for £8, with an estimated delivery time of 1–2 business days. Full details are on our shipping policy page.

Frequently asked questions

Do windscreen frost covers actually work?

Yes, when they are fitted correctly. The frost forms on the cover instead of the glass. They work best on dry glass, fitted before the temperature drops and held firmly against the wind.

Can I put a windscreen cover on a wet windscreen?

It is better not to. Moisture trapped underneath can freeze and stick the cover to the glass. Wipe the screen dry first where you can.

Is it illegal to drive with a partly frozen windscreen?

You must be able to see clearly through all your windows before driving. Clearing only a small patch is unsafe and can lead to a fine and penalty points.

Why does the inside of my windscreen freeze?

It is usually caused by moisture inside the car, from wet clothes, footwear or condensation. Reducing damp in the cabin and keeping the glass clean helps.