What should you check on your car before winter?
Battery, screenwash, wipers, lights, tyres and a kit in the boot. Finally, check when the MOT runs out. That's the whole list, and most of it takes ten minutes on a Saturday morning.
Only some of it is law. The rest is advice from two different places. Knowing which is which tells you what can't wait.
| Item | Who says so | Status |
|---|---|---|
| Wipers and washers working | Construction and Use Regulations, reg 34 | Law |
| Lights clean, working and not dazzling | Highway Code Annex 6, with a MUST, and the Lighting Regulations | Law |
| Battery well maintained | Highway Code Annex 6, "Before winter" | Advice |
| Antifreeze in radiator and washer bottle | Highway Code Annex 6, "Before winter" | Advice |
| Tyres inflated to the maker's pressures for the load | Highway Code Annex 6, with a MUST | Law |
| Tyre pressures checked weekly, cold | Highway Code Annex 6 | Advice |
| Emergency kit in the car | Highway Code rule 228 | Advice |
| Screenwash rated to -15C, new wiper blades yearly | Met Office page, drawing on RAC advice | Trade opinion |
"Law" means a rule you can be stopped for breaking. "Advice" means the Highway Code tells you to, but there's no offence attached. "Trade opinion" means a breakdown firm or similar recommends it, and we've named them.
This is part of our wider guide to running a used car.
What does the Highway Code tell you to do before winter?
Two things, in one short line. Annex 6 of the Highway Code says: "Before winter. Ensure that the battery is well maintained and that there are appropriate anti-freeze agents in your radiator and windscreen bottle."
That's it. There's no MUST in it, so it's advice. The same page does carry MUSTs for lights and windows, which we come to below.
Annex 6 also sets a rhythm for the whole year. Check tyre pressures weekly, before you set off, "when tyres are cold". It warns that warm tyres "may give a misleading reading". Fluid levels get the same weekly check.
Then there's rule 228, in the adverse weather section. In winter, check the forecast for ice and snow warnings. It says don't drive in those conditions unless the journey is essential, and lists a kit to carry if you do. The kit is in its own section further down.
Why does winter kill car batteries?
Because a tired battery that scraped through summer gets found out on the first cold morning. The Met Office's winter checks page says battery problems cause more RAC call-outs in winter than anything else. That's the RAC's own call-out data, not a UK-wide figure.
So get the battery tested now. Garages and breakdown firms can do it, and some fast-fit chains do it for nothing. You'll see "replace it every five years" quoted online. We couldn't find an official source for that, so treat it as a rule of thumb and trust the test instead.
If the car has sat for a week and starts slowly, that's your warning. Get it checked before the morning it fails.
Electric cars have a 12-volt battery too. It runs things like the locks, the screens and the car's computers, and it can go flat like any other. Your handbook will say how the car looks after it.
Antifreeze and screenwash: what goes in?
Coolant is a mix of water and antifreeze, and the right type and mix is in your handbook. Don't guess at a ratio. Different engines take different coolants, and the wrong one can damage the system.
If the level has dropped, top it up with the type the handbook names. If it keeps dropping, the car has a leak, and that's a garage job.
Screenwash is simpler. The Highway Code wants anti-freeze agents in the windscreen bottle, and plain water isn't one. Water freezes in the pipes and on the glass, and then you've no washers at all. That matters, because washers are a legal item, as the next section explains.
The Met Office page suggests a screenwash rated to at least -15C. That's its recommendation, not a rule. Check the bottle, because how cold it copes with depends on how strongly you mix it, and a weak summer mix protects far less.
Wipers, washers and lights: the legal bit
Three things here are law. Your wipers and washers must work. Your lights must be clean and working. And you must use your headlights when you can't see far.
Wipers and washers
Regulation 34 of the Road Vehicles (Construction and Use) Regulations 1986 covers this in England, Wales and Scotland. A car must have efficient wipers that can clear the windscreen. It must have a washer that can clean the swept area.
Paragraph 6 is the winter one. Every wiper and washer "shall at all times while a vehicle is being used on a road be maintained in efficient working order and be properly adjusted." A split blade or an empty, frozen washer bottle doesn't meet that.
Breaking a construction and use rule is an offence under section 42 of the Road Traffic Act 1988. We haven't pinned down the exact penalty for this one, so we won't quote a figure.
Northern Ireland has its own regulations. Regulation 39 of the Motor Vehicles (Construction and Use) Regulations (Northern Ireland) 1999 says the same thing almost word for word. The only version online is the one as originally made, so check for later amendments before relying on the detail.
The MOT checks both. In the inspection manual, a wiper "not operating or missing" is a major defect. So is a blade "missing or obviously not clearing the windscreen".
Washers "not working or not providing sufficient fluid to clear the windscreen" are a major defect too. Any of those fails the test.
The Met Office page recommends new blades every 12 months. That's trade advice. Still, blades are cheap, and the legal duty is on you to keep them working.
Lights
Annex 6 says lights, indicators, reflectors and number plates "MUST be kept clean and clear". Lights also "MUST be properly adjusted to prevent dazzling other road users". The working part comes from regulation 23 of the Road Vehicles Lighting Regulations 1989, which says lamps must be "in good working order". Walk round the car with everything on and get someone to press the brake.
Rule 226 says you MUST use headlights "when visibility is seriously reduced, generally when you cannot see for more than 100 metres". Note the word "generally". The 100 metres is a guide to help you judge, not a line someone measures.
Fog lights have their own rule. Rule 236 says you MUST NOT use front or rear fog lights unless visibility is seriously reduced, because they dazzle and can hide your brake lights. You MUST switch them off when it clears.
Our MOT checklist covers how lights are tested. If you're changing a bulb, our guide to LED headlight bulbs and the MOT is worth a read first.
Do you need winter tyres?
Not by law, anywhere in the UK. Whether they're worth buying depends on where you live and how you drive. Our guide to winter tyres and the law covers that decision, the insurance question and the rules abroad.
The weekly check belongs here. Annex 6 says tyres "MUST be correctly inflated" to the maker's figure for the load you're carrying, so this one is law.
It also says check pressures weekly and cold, against the handbook. Many cars also carry the figures inside the driver's door. Tyre pressure falls as the air gets colder, so a tyre that looked fine in September may be low now.
The Met Office page also reports the RAC's view that 3mm of tread is the sensible minimum for icy conditions. The legal minimum is lower, and the sibling article explains it.
What should you keep in the car?
Start with the Highway Code's list, then add the Met Office's extras. Keep the two apart in your head. One is the Code's advice, the other is one organisation's suggestion.
Rule 228's emergency kit:
- de-icer and ice scraper
- torch
- warm clothing and boots
- first aid kit
- jump leads
- a shovel
- a warm drink and emergency food
The rule says to take it "in case you get stuck or your vehicle breaks down". It's advice, and there's no offence for travelling without it.
The Met Office's own basic winter kit adds a few more. Warning triangles, ideally two. Sunglasses, for low winter sun. An in-car phone charger, a portable power bank and a blanket.
It also says to fill the tank before setting off, which costs nothing to follow.
When the car has frozen overnight, our guide to defrosting your car quickly and legally covers the method and the rules.
What about electric cars?
Range falls in cold weather. How much depends on the car, your speed and the temperature. You'll see percentages quoted online from magazine and motoring-club tests. They vary a lot from car to car and test to test, so take them as a rough idea rather than a figure for your car.
Plan for less range than the dashboard promised in summer. Charge to a higher level before a long trip and know where you'd stop.
Many EVs let you warm the cabin, the battery or both before you set off. Kia says that when the car is plugged in while it warms the battery, the energy is "drawn from the power source, not the battery itself". Whether yours does this, and how to set it, is in the handbook or the maker's app. The 12-volt battery point from earlier applies too.
If you're buying one this winter, our guide to checking a used electric car covers the battery questions to ask.
What if the car will sit unused all winter?
You have two choices. Keep it taxed and insured, or declare it off the road with a SORN, a Statutory Off Road Notification to DVLA. There's no third option.
Gov.uk is blunt about it: "You must insure and tax your vehicle if you do not have a SORN." You need a SORN if the car isn't taxed, or isn't insured "even for a short time". Without one, you'll "automatically be fined £80".
A SORN car can't sit on a public road. It has to be in a garage, on a drive or on private land. You can only drive it on a public road to or from a pre-booked MOT or other test. Anything else risks prosecution and a fine of up to £2,500.
Our guide to SORN covers how to declare one and how to end it. If the car stays taxed and insured, no SORN is needed.
If it's old enough to need an MOT, that has to stay valid too. Gov.uk says you can't drive or park on the road once the MOT has run out. The exceptions are driving to a pre-arranged MOT test, or to or from somewhere to be repaired.
I'd keep it insured if the car is worth anything to you. Theft and weather damage don't stop because the car isn't moving. A SORN doesn't stop you insuring the car off the road, and some insurers sell laid-up cover for exactly that, so ask yours.
Is the MOT due this winter?
Check the date now, not when the reminder arrives. Our free MOT check shows the expiry date from the plate, plus any advisories on tyres, wipers and lights from the last test.
You can take the test up to a month, minus a day, before it expires and keep the same renewal date. Take it earlier than that and the renewal date resets. Gov.uk says you can be fined up to £1,000 for driving without a valid MOT. Our guide to how long an MOT is valid for has the detail.
A winter MOT is a good time to book a service too. The battery test can go on the same job sheet.
Then there's what the car costs to run over the year. Our free car check includes a running-costs estimator covering fuel, road tax and the MOT test fee. Our guide to used car running costs covers the rest.
Road salt does its damage over winter too. Our piece on regional corrosion and MOT failure looks at where that bites hardest.
Common questions
What should I check on my car before winter?
Battery, screenwash and coolant, wipers, lights and tyre pressures. Then put a kit in the boot and check the MOT date. The Highway Code's own "before winter" line is short. It says keep the battery well maintained and have antifreeze in the radiator and the washer bottle.
Is it a legal requirement to have antifreeze in your car?
No. The Highway Code tells you to have it, in Annex 6, but there's no MUST and no offence. What is law is that your wipers and washers work whenever the car is on the road. A frozen washer bottle fails that, which is the real reason to use winter screenwash.
What should be in a winter emergency kit for a car?
Rule 228 of the Highway Code lists de-icer and an ice scraper, a torch, warm clothing and boots, and a first aid kit. It adds jump leads, a shovel, and a warm drink and emergency food. That list is advice, and there's no offence for driving without it. The Met Office's basic winter kit adds warning triangles, sunglasses, a phone charger and a blanket.
Do I need to tell my insurer or SORN my car if I'm not using it this winter?
You must either keep the car taxed and insured or declare a SORN. If it has a SORN it must stay off the public road. A SORN doesn't stop you insuring the car off the road, and some insurers sell laid-up cover, so ask yours what they need to know.
Do electric cars lose range in cold weather?
Yes. The amount varies with the car, the temperature and how you drive. Test figures online differ widely between cars and tests. Plan on less range than the summer figure and charge up before a long trip.
When should I replace my windscreen wipers?
When they start to smear or judder. The Met Office page suggests every 12 months as a rule of thumb. By law they must be kept in efficient working order whenever the car is on the road, and a blade that isn't clearing the screen is a major MOT defect.