A mild autumn can change quickly. Your windscreen may be clear when you go to bed and covered by a hard layer of frost by the time you need to leave. Preparing before the first properly cold morning is easier than trying to solve the problem when you are already late.
The most reliable routine is simple: check the forecast, cover the outside of the windscreen before temperatures fall, keep a proper scraper and de-icer in the car, and allow enough time to clear every window before driving. This guide explains how to stop your windscreen freezing where possible and how to de-ice it safely when frost still forms.
Quick answer: how to stop a windscreen freezing overnight
- Fit a secure, purpose-made windscreen frost cover before the temperature drops.
- Park in a garage, carport or sheltered position when one is available.
- Remove damp coats, towels and other wet items that add moisture inside the car.
- Keep a plastic ice scraper and suitable de-icer ready rather than relying on hot water.
- Check the overnight forecast so a frosty morning does not catch you by surprise.
No method can guarantee that every part of a parked car remains frost-free. The aim is to reduce how much ice forms and make the remaining frost quicker and safer to clear.
Why does a car windscreen freeze?
Frost forms when the glass becomes cold enough for moisture in the air to freeze onto it. A windscreen is exposed to the night sky and can lose heat quickly, particularly on a clear, calm night. That is why you can sometimes wake to an iced windscreen even when the air temperature shown by a weather app appears to be slightly above freezing.
Ice can also form on the inside of the glass when moisture is trapped in the cabin. Wet shoes, damp mats, coats, umbrellas and persistent condensation all add water vapour. If the inside surface becomes cold enough, that moisture can freeze.
1. Use a windscreen frost cover
A cover creates a barrier between the windscreen and the cold, damp air. It will not warm the entire car, but it can prevent or greatly reduce the layer of frost directly on the covered area. In the morning, remove the cover and deal with any exposed edges, side windows and mirrors separately.
Choose a cover that is large enough for your windscreen and can be secured without obstructing or damaging anything. Our windscreen frost cover is designed for overnight use and should always be removed completely before driving.
How to fit it properly
- Start with a parked car and a reasonably clean windscreen.
- Position the cover so the main viewing area is protected.
- Secure it using the product's fittings rather than improvised objects that could scratch the paint or glass.
- Check that it cannot flap loose or create a hazard in strong wind.
- Remove and dry the cover before storing it after use.
2. Choose the most sheltered parking position available
A garage or covered parking space gives the best protection. If that is not available, parking close to a building or hedge may reduce exposure, provided the location is legal and safe. Even a small amount of shelter can make the morning job easier, although local conditions vary.
Do not sacrifice safe parking for a slightly less frosty windscreen. Avoid blocking pavements, entrances or visibility at junctions, and never park somewhere simply because it appears more sheltered if parking there is not permitted.
3. Reduce moisture inside the car
External frost and internal condensation are different problems, but both can leave you waiting for clear glass. Remove wet clothing, towels and umbrellas when you finish a journey. Shake excess water from footwear before getting in where practical, and deal with persistently damp carpets or mats rather than allowing them to stay wet.
Use the vehicle's ventilation and demisting controls during the journey, following the handbook for your car. If the glass regularly freezes on the inside, investigate where the moisture is coming from. A leaking seal or water entering the cabin needs fixing rather than masking with de-icer.
4. Prepare before the cold night
Keep a plastic scraper and de-icer where you can reach them without first opening a frozen boot. Make sure the scraper edge is clean and undamaged, because grit trapped against the blade can mark the glass.
If snow is possible, an extendable snow brush and ice scraper helps you reach more of the vehicle without using improvised tools. Store the rest of your cold-weather kit together so that it is easy to find; the Seasonal Car Accessories collection brings the current winter products into one place.
How to de-ice a windscreen safely
When frost has already formed, allow enough time to clear the car properly. The goal is not a small viewing hole in front of the steering wheel. You need clear vision through the windscreen, side windows and mirrors before moving off.
Step 1: clear loose snow first
Brush loose snow from the roof, bonnet, lights, windows and number plates. Snow left on the roof can slide forward under braking or blow into another road user's path. The Highway Code, Rule 229, says that before setting off you must be able to see, all snow and ice must be cleared from your windows, lights must be clean and number plates must be visible.
Step 2: use the car's demisting system
Start the vehicle as directed by its manufacturer and select the correct windscreen demisting setting. Heated windscreens and mirrors should be used according to the handbook. Stay with the vehicle while it is running and do not begin the journey until visibility is clear.
Step 3: apply de-icer if needed
Use a de-icer intended for automotive glass and follow its instructions. Give it time to soften the frost instead of immediately forcing the scraper through a hard layer. Keep the spray away from your eyes and store it as directed on the container.
Step 4: scrape with a proper plastic tool
Work methodically across the glass with a clean plastic scraper. Use steady pressure rather than striking the windscreen. Clear the corners and the area around the wiper blades as well as the centre.
Step 5: clear every window and mirror
Finish the side and rear windows, mirrors, lights and number plates. Lift or free the wiper blades carefully if they are frozen to the glass; do not switch the wipers on while they are stuck. Wait until the windscreen is fully clear and the inside has demisted before driving.
What not to do with a frozen windscreen
Do not pour boiling water over the glass
A sudden temperature change can damage cold glass, and the water may refreeze around the car. The RAC's current de-icing guidance advises avoiding hot or boiling water and using a suitable scraper and de-icer instead.
Do not use metal or a bank card as a scraper
Improvised tools can scratch the glass, damage seals or snap in your hand. A purpose-made plastic scraper is inexpensive and shaped for the job.
Do not rely on the windscreen wipers
Wipers are not ice scrapers. Operating them while they are frozen to the windscreen can damage the rubber blades or strain the mechanism. Free the blades and clear the glass first.
Do not drive with only a small patch cleared
A partially cleared windscreen restricts your view of pedestrians, cyclists and traffic approaching from the sides. Clear all the glass you need for full visibility, not just the area directly in front of the driver.
Frost cover, de-icer or scraper: which do you need?
| Item | Best used for | Limitation |
|---|---|---|
| Windscreen frost cover | Reducing overnight frost on the covered glass | Does not protect every window or exposed edge |
| Automotive de-icer | Softening an existing layer of frost | Must be stored and used according to its instructions |
| Plastic ice scraper | Physically removing softened frost and ice | Requires time and access to the whole window |
| Snow brush | Removing loose snow from larger areas | Not a substitute for clearing bonded ice |
For most UK drivers, the useful combination is a frost cover for prevention plus a scraper for the areas the cover does not protect. De-icer is a helpful backup for harder frost.
Frequently asked questions
Can I put a towel or cardboard on my windscreen?
It may provide some temporary coverage, but absorbent material can become wet, freeze to the glass or blow loose. A purpose-made cover with proper securing points is the more dependable option.
Why is my windscreen frozen on the inside?
There is too much moisture inside the cabin for the temperature. Remove wet items, dry damp mats, use the ventilation system correctly and investigate leaks if the problem keeps returning.
Should I leave the engine running to warm the windscreen?
Use the vehicle's demisting controls as instructed by the manufacturer, remain with the car and do not drive until visibility is clear. Avoid leaving a running vehicle unattended.
Does a frost cover protect the side windows?
A windscreen cover protects only the area it physically covers. Side windows, mirrors, lights and number plates still need checking and clearing before the journey.
When should I put the frost cover on?
Fit it to a parked car before the temperature falls and before frost begins to form. Check the forecast in the evening rather than waiting until the glass is already frozen.
A simple evening and morning routine
The night before
- Check the overnight forecast.
- Remove damp items from the cabin.
- Fit the frost cover securely.
- Place the scraper and de-icer somewhere accessible.
- Allow extra time for the following morning.
Before driving
- Remove and store the frost cover.
- Brush away loose snow.
- Use the demister and de-icer where needed.
- Scrape every frozen window and mirror.
- Check the lights, wipers and number plates.
- Move off only when you have full visibility.
Prepare before the first frost
The best time to prepare is before a cold morning is forecast. A properly fitted windscreen cover can reduce the work, while a clean scraper and suitable de-icer deal with whatever remains. The important part is allowing enough time to clear the entire car rather than rushing onto the road with restricted visibility.
For a wider cold-weather packing list, see our winter car essentials checklist for UK drivers.
Browse our winter and seasonal car accessories for the frost cover and extendable scraper featured in this guide. Free UK delivery is available with no minimum spend.