Fact or frostbite? The truth behind common winter car myths

30 November 2025

Some winter driving tips may sound helpful, but they are more fiction than fact. In some cases, they could even leave you shivering outside your car or facing an unexpected fine.

We’re here to clear up the misconceptions and help you be prepared, protected and confident behind the wheel, whatever the weather throws your way.

Easy As Hack

Driving in wellies isn’t illegal, but if your footwear affects how you control the car, you could still end up with a fine.

At a glance

Four of the most common winter driving myths that are actually false:

Driving in Wellington boots is illegal
Warming up your engine is necessary (not if it’s a modern car)
Deflating tyres increases traction in snow
Winter tyres are necessary

WINTER DRIVING MYTHS

Winter driving myths can cause more confusion than clarity when the temperature drops, with many of the things we’ve been told over the years no longer applying to modern cars.

Here are our essential winter car tips that separate fact from mere frostbite!

1: YOU NEED TO WARM UP YOUR ENGINE FOR 10 MINUTES BEFORE DRIVING

Fiction and some fact. Letting the engine idle before starting is an urban legend with some truth to it, but its necessity depends on your car’s age and engine type.

You may need to wait about three minutes (and occasionally up to 10) for a vehicle with a carburettor, built before modern electronic fuel injection in the late 1980s, to warm up. In the meantime, you can take the opportunity to squeegee any dew off the windows and mirrors!

Most of us who drive cars with fuel-injected petrol or diesel engines can start the vehicle up and be on our way in around 30 seconds, giving the engine time to lubricate its components, which improves performance and extends its life.

Electric and plug-in hybrid car drivers may also want to warm up (‘pre-condition’) an EV battery while it’s connected to the mains for charging before driving in cold weather. Warming gives you full power and range and has the advantage of making the cabin toasty before you set off.

Standard hybrids, like the Toyota Prius, don’t require pre-conditioning – you can simply drive off while the software sorts it out.

Learn how to warm up your car engine.

2: WINTER TYRES AREN’T NECESSARY IN THE UK

Partially fact. In the UK, there’s no legal requirement to have winter tyres, as the seasons are relatively mild. However, they can make a big difference especially in rural areas and the coldest regions, including the Scottish Highlands, the Hebrides, the North Pennines and Northern Ireland.¹

Winter tyres are made with more natural rubber than standard ones, which keeps them softer and more flexible when temperatures drop. That means better grip and control on cold roads especially when temperatures drop below 7^oC². Their tread patterns are also designed to handle wet, icy or snowy surfaces, helping reduce the risk of aquaplaning and keeping you safer when it matters most.

You do not need to tell most insurers if you have changed to winter tyres.

Learn how to change a car tyre.

3: HOT WATER IS THE BEST WAY TO DEFROST YOUR WINDSCREEN

Fiction. It might seem like a quick fix, but pouring hot or even warm water, whether directly from a kettle or using a bag, onto a frozen windscreen can cause thermal shock. That sudden change in temperature could crack the glass, leaving you with a much bigger problem than frost.

You also risk creating a fresh ice layer because warm water refreezes faster than cold water.

Using hot water repeatedly increases the likelihood of the crack spreading, which could turn a chip repair into a windscreen replacement. Repairing a chip is often covered at no cost through your car insurance if you use an approved repairer, but an excess typically applies for a replacement.

Here’s what to do if you get a chip.

4: IT’S ILLEGAL TO DRIVE IN WINTER BOOTS OR WELLIES

More fiction. Driving in Wellington boots or other thick-soled shoes is not illegal. In fact, there’s no specific law prohibiting the wearing of flip-flops or driving barefoot.

This urban myth likely stems from a misunderstanding of Rule 97 of the Highway Code, which relates to footwear that hinders your ability to control the vehicle. A police officer may decide to charge you if they determine that your boots contributed to driving without due care or dangerous driving under Section 3 of the Road Traffic Act 1988.³

The penalties range from an on-the-spot fine of £100 and 3 penalty points on your licence, up to 9 penalty points and a £5,000 fine if the case reaches court.

Check out our guide to driving conviction codes.

5: YOU CAN BE FINED FOR LEAVING THE ENGINE RUNNING TO DEFROST YOUR WINDSCREEN

Fact. You can be fined for leaving your engine running while defrosting the windscreen on a public street. An officer can issue you with a £20 to £80 fixed penalty notice for refusing to turn it off under Regulation 98 of the Road Vehicles (Construction and Use) Regulations 1986.³

However, it is not illegal to leave your car idling on your driveway or other private property. Discover why car idling is harmful.

6: SALT ON ROADS ONLY HELPS WITH SNOW

Fiction. When local authorities spread salt on the roads (a process known as gritting), it does more than just help melt the snow. Gritters can also use rock salt to prevent ice and frost from forming, making the roads safer to drive on. Additionally, this pre-treatment makes it easier to clear the snow.

The Salt Association⁴ states that salt lowers the freezing point of water and can be effective in temperatures as low as -10 degrees Celsius. According to the Met Office,⁵ climate change means the UK is likely to face an average temperature of 10 degrees Celsius in the future, making this de-icing method still ideal.

7: IT’S ILLEGAL TO DRIVE WITH ICE ON YOUR WINDSCREEN

Fact. Yes, it’s unlawful to drive with ice on your windshield. Rules 228 to 231 of the Highway Code⁶ address driving in icy and snowy conditions. Rule 229 states: ‘Before you set off on snowy or icy roads, you MUST be able to see, so clear all snow and ice from your windows.’

Make sure to clean your lights, mirrors, and licence plates, and don’t forget to thoroughly de-ice and defog the windows. While it’s tempting to hit the road quickly during winter, make sure your windscreen is fully cleared before you go.

If you fail to de-ice your car, you could face a £100 fine and receive 3 penalty points on your licence.

Learn how to stay safe while driving on icy roads.

8: SNOW AND ICE ONLY NEED TO BE CLEARED OFF A VEHICLE’S WINDOWS

Fiction. It’s not true that you only need to clear snow and ice off a car’s windows. According to Rule 229 of the Highway Code, lights, mirrors and number plates must also all be visible. You are considered guilty of an offence if the registration is unclear or difficult to read.⁷

There is no offence specifically associated with clearing snow from the roof or bonnet of your vehicle. A police officer may charge you with ‘driving without due consideration’ or ‘using a motor vehicle in a dangerous condition’ if a significant amount of snow falls into the path of other road users or slides onto your windscreen, obstructing your vision.

Read our tips for driving in frosty conditions.

9: DEFLATING YOUR TYRES GIVES YOU BETTER TRACTION IN THE SNOW

Fiction. This winter driving myth probably originates from off-road racing, where underinflated tyres create a larger surface area, enabling them to grip the sand and earth more effectively.

It doesn’t have the same impact on snow and icy roads. Deflating your tyres can be dangerous, because it results in excessive traction and reduced grip, increasing the risk of an accident. Deflating your tyres will make the car harder to control and can cause premature tyre wear.

Maintaining the correct tyre pressure should be an essential part of a driver’s winter car care routine. You could face a fine and penalty points for interfering with the safe operation of a vehicle if your tyre pressures are not suitable for the load or driving conditions.⁸

To enhance performance and grip, choose winter tyres and inspect them more frequently during the winter months.

How to find the right tyres.

10: YOU’RE COVERED IF YOUR CAR IS STOLEN WHILE LEFT RUNNING ON A COLD MORNING

Fiction. Unfortunately, this is another winter car myth. Your insurance may not cover you if you stay indoors while the car is defrosting and an opportunistic thief steals it (a form of theft called frostjacking).⁹

Review your insurance policy for clauses related to ‘keys-in-car’ or ‘vehicle-left-unattended’, as these may exclude related claims. It’s best to remain with the vehicle at all times while it defrosts to avoid the risk of not receiving a payout.

Note: Your insurance is generally still covering you if you turn on the defroster and fan and walk around the vehicle with an ice scraper. It’s whether the vehicle is unattended with the keys inside that insurers are concerned about.

Learn how to prevent car theft.

11: SLOWING DOWN IS ALL YOU NEED TO DO TO DRIVE SAFELY ON SNOW AND ICE

Fiction. Many people believe you just need to slow down to drive safely in wintry conditions, but it’s more to do with driving smoothly and steadily.

Controlled driving, avoiding sudden braking or sharp acceleration, is the best way to maintain tyre traction and prevent skidding into danger.

Find out more about Ageas car insurance.