The best ways to defrost and remove ice from your windscreen

What causes my windscreen to freeze?

Ice can form on your windscreen when cold temperatures meet moisture in the air. Because glass loses heat quickly, moisture droplets can freeze when they come into contact with a cold windscreen.

Frost is most likely to form overnight in clear, cold and still conditions, particularly when the air temperature drops to about 2.2°C or below.

The best ways to defrost and de-ice your windscreen

Commercial de-icing sprays

Commercial de-icers can help melt windscreen ice and reduce refreezing. Look for “de-icer” on the label and always follow the instructions. Many contain methanol, so protective eyewear may be recommended. Some products may also contain ethylene glycol, which is hazardous to pets, so keep the lid tightly closed and store it in a safe, well-ventilated place.

Ice scrapers

A plastic ice scraper is one of the safest ways to remove ice from your windscreen. Use firm, gentle pressure and work from the top down, pushing the ice away as you go. For stubborn patches, use the scraper’s edge or corner for extra leverage. Never use metal items, as they can scratch the glass

Caught out without an ice scraper? An old plastic credit card or similar can work in a pinch.

Use your car's defrost setting

Start the engine and turn on the windscreen defrost function. Set the heater to its maximum setting so warm air can gradually melt the ice. You can also use the rear demister to clear the back window.

Never leave your car unattended while the engine is running. Under Victorian road rules, you must switch off the engine if you’ll be more than three metres from the vehicle. Some newer cars have remote heating technology, which can help de-ice the windscreen while the vehicle remains secure.

Lift up your windscreen wipers

If you expect frost, lift your windscreen wipers after parking to stop them freezing to the glass.

If the wipers are already frozen, don’t switch them on. Use de-icer around the blades or the windscreen defrost function to loosen them first. Running frozen wipers can strain the motor and damage the blade rubber, especially on a dirty or frosted windscreen.

Don't forget to de-ice your side mirrors and windows

Don’t forget your side mirrors, rear window and side windows; they also need to be clear before you drive. Use de-icer and a plastic ice scraper to safely remove ice and maintain visibility.

What not to do when de-frosting your windscreen: common mistakes

There are some common mistakes that people make when trying to de-ice their windscreen. Here are some unwise practices to avoid:

Don't pour hot water or warm water onto a windscreen

One of the biggest mistakes people make is using hot water or even warm water to de-ice their icy windscreen. While it may seem like a quick and easy solution, the sudden temperature change can cause frozen glass to crack, potentially leading to costly repairs or a full windscreen replacement.

Don't use salt or vinegar to remove windscreen ice

Another mistake is using salt or vinegar to help melt ice on your windscreen. These substances can damage your car’s paint and glass. Salt, in particular, can cause corrosion over time, leading to long-term vehicle damage.

Beware of online 'hacks' to remove ice from your windscreen

The internet is full of de-icing “hacks”, but some can damage your windscreen, paintwork or other parts of your vehicle. Hazardous substances can also pose health risks, including serious eye irritation. Stick to methods that safely clear your windscreen without causing damage.

How to prevent windscreen frost and ice buildup overnight

These proactive measures can help prevent ice forming on your windscreen in the first place. 

Park undercover 

If you have access to a carport or garage, parking undercover should help reduce the risk of a frosted windscreen. 

Use a windscreen cover

A good-quality windscreen cover can save time on frosty mornings by helping prevent ice from forming overnight. Place it over your windscreen after parking, then remove it in the morning to reveal clear glass. A note of caution, however: if you're visiting or live in alpine areas, or you're going on a skiing holiday, heavy snowfall overnight can make it difficult to remove the windscreen cover.  

Anti-frost windscreen spray

Anti-frost windscreen sprays can help prevent ice and frost from forming by creating a thin protective layer that repels moisture. Apply them before cold weather sets in and always follow the safety instructions on the container.

Check your windscreen regularly

Inspect your windscreen regularly for cracks or chips, especially in winter. Cold weather can cause small cracks to spread, so arrange repairs promptly if you notice any damage.

Make sure your wipers are also in good condition, as worn blades can make de-icing harder and reduce visibility. If you need a windscreen replacement, chip repair or integrity check, a qualified professional can help.

In regards to car insurance, windscreen cover is usually an optional extra, so check your car insurance policy to see if you're covered.

RACV's winter driving guides to help keep you safe

• Driving safely in fog, rain, snow, and poor-visibility conditions
• Safety tips for driving in the snow and on icy roads
• How to maintain your car in winter and cold weather
• What you need to know about car batteries
   

Safety considerations when de-icing your windscreen

Many newer cars have windscreen sensors for forward collision cameras and other driver assistance features, and frost or dirt can affect how they work. If sensors are located on the front grille or bumper, make sure these areas are also clear before driving.

Follow your manufacturer’s advice for keeping sensors clean and check your owner’s manual so you understand how these systems work in your car. If you can’t resolve an issue, contact roadside assistance or a trusted mechanic.

If you start the engine to help de-ice your windscreen, don’t leave the vehicle unattended. Under Victorian road rules, you must switch off the engine if you are going to be more than three metres from the vehicle. Leaving your car running and unattended can also increase the risk of theft.

Before driving, make sure all ice and frost has been removed so you have clear visibility through your windscreen, windows and mirrors.

Frequently Asked Questions

^{The information provided is general advice only. Before making any decisions please consider your own circumstances and the Product Disclosure Statement and Target Market Determinations. For copies, visit racv.com.au. As distributor, RACV Insurance Services Pty Ltd AFS Licence No. 230039 receives commission for each policy sold or renewed. Product(s) issued by Insurance Manufacturers of Australia Pty Ltd ABN 93 004 208 084 AFS Licence No. 227678.}