A few summers ago, a UK heatwave was a novelty. A handful of unusually warm days, a scramble for paddling pools, then back to normal. That’s no longer quite the case. Heatwaves are arriving more often, lasting longer, and reaching temperatures that the UK’s roads, vehicles, and drivers simply aren’t built for. At the time of writing, the Met Office has issued a rare red extreme heat warning, with parts of England and Wales expected to exceed 37°C and some areas potentially reaching 40°C.

If you’re learning to drive, this might be the first time you’ve had to think about heat as a road safety issue rather than just an excuse to wind the windows down. But hot weather changes almost everything about a journey: how your car behaves, how the road surface behaves, and — perhaps most importantly — how other people behave. This guide walks through all of it, in plain terms, so you can drive confidently whatever the thermometer says.

Why Hot Weather Is a Genuine Driving Hazard

It’s easy to assume that bad driving weather means rain, ice, or fog. Heat doesn’t immediately spring to mind. But extreme heat affects your concentration, your vehicle’s reliability, and the very surface you’re driving on. The UK Health Security Agency has gone as far as issuing heat health alerts that warn of impacts not just on vulnerable groups, but on the general population — and that includes anyone behind the wheel.

For a learner, this matters for two reasons. First, your test or lesson doesn’t get cancelled just because it’s hot, so you need to know how to cope. Second, the habits you build now — checking the car, planning the journey, watching for other people’s odd behaviour — are exactly the habits that keep you safe for the rest of your driving life.

Pre-Journey Checks: Your Car Feels the Heat Too

Before you even turn the key, a few extra checks in hot weather can be the difference between a smooth journey and a roadside breakdown.

Tyres. Heat causes the air inside your tyres to expand, which increases tyre pressure. At the same time, hot road surfaces put more stress on the rubber. The combination means tyre blowouts become noticeably more likely in extreme heat, especially at motorway speeds. Before any journey, check your tyre pressures when the tyres are cold (first thing in the morning, before you’ve driven anywhere), and look closely for cracks, bulges, or anything embedded in the tread. If you’re on a driving lesson, your instructor should be doing this as part of your “show me, tell me” practice anyway, but it’s worth understanding why it matters more in summer.

Coolant and oil. Your engine relies on coolant to stop it overheating, and in hot weather it’s working harder to do that job. Check the coolant level when the engine is cold (never open the cap on a hot engine) and top up if needed. Low engine oil can also cause overheating, so check that too.

Windscreen washer fluid. Dust, pollen, and squashed insects build up fast in summer, and a half-empty washer bottle is no use when you suddenly need to clear your view. Top it up before you set off.

Air conditioning and ventilation. If you have air-con, make sure it’s actually working before a long or important journey — a regas is far cheaper than a breakdown. If you don’t have air-con, plan how you’ll keep cool and keep your windows demisted (yes, even in summer, sudden temperature changes between an air-conditioned car and humid air outside can cause misting).

Water and sun protection. Keep a bottle of water in the car for yourself, and a cool bag for any drinks or snacks you’re carrying. Sunglasses are genuinely a safety item in bright glare, not just a style choice — but avoid very dark “Category 4” lenses, as these let in too little light for safe driving, particularly through tunnels or in shaded sections of road.

Timing. Where you have any choice in the matter, avoid travelling in the hottest part of the day, typically early afternoon. Early morning or evening journeys are cooler for you, cooler for your car, and often quieter on the roads too.

How Road Conditions Change in Extreme Heat

This is the one most learners haven’t even considered: the road surface itself can change in extreme heat. UK roads are mostly made from tarmac — stone bound together with bitumen — and bitumen softens as temperatures climb. In genuinely extreme conditions, ground-level temperatures can exceed air temperature significantly, and roads have been known to visibly soften, becoming sticky and shiny, sometimes pulling away in chunks under the weight of vehicles.

What does this mean for you as a driver?

• Reduced grip. A softened road surface doesn’t grip your tyres in the way you’re used to, particularly under braking or cornering.
• Loose debris. Softened tarmac can break up, leaving grit, stone, and sticky residue on the surface, which behaves a bit like a very localised gravel trap.
• Gritters in summer. Don’t be alarmed if you see gritting lorries out in a heatwave. Local authorities sometimes spread granite dust on the worst-affected roads to stabilise the softened surface and improve grip. It looks like a winter scene in the middle of a heatwave, but it’s a normal precaution.
• Road closures. In severe cases, councils have temporarily closed roads that have melted badly enough to be unsafe or to be causing damage to vehicles. If you see warning signs or diversions on a hot day, take them seriously.

If a road surface looks shiny, feels different under the tyres, or you can smell tarmac strongly, ease off your speed and increase the distance to the vehicle in front. Treat it a little like you would a wet road — reduced confidence in your grip, smoother inputs, more following distance.

Other Drivers: Why Everyone Gets a Bit Worse in the Heat

One of the most underrated hazards of a heatwave isn’t the road or the car — it’s everyone else on it. Heat genuinely affects human concentration, mood, and decision-making, and you’ll notice the difference in how people drive.

Fatigue and slower reactions. Heat is tiring. Combined with poor sleep — and the Met Office has specifically flagged “tropical nights” where temperatures don’t drop below 20°C, making it much harder for people to recover overnight — drivers are often operating on less rest than usual. Tired drivers react more slowly and make more mistakes.

Shorter tempers. It’s a well-observed pattern that people become more irritable in sustained heat, and that shows up on the road as more impatience, more horn use, closer following, and more aggressive overtaking. Give other drivers a wider margin than usual and don’t take the bait if someone seems to be in a bad mood.

More distraction. Drivers fiddling with air conditioning controls, sun visors, or trying to angle a phone to block glare are paying less attention to the road than they should be. Assume the driver ahead of you might be distracted, particularly at junctions and roundabouts.

More vulnerable road users about. Warm weather brings out cyclists, motorcyclists, walkers, and horse riders in far greater numbers, often on routes you wouldn’t expect to be busy. Give them plenty of space and time, and slow down on bends and blind sections where someone could appear unexpectedly.

More breakdowns ahead of you. Breakdown providers see a sharp rise in call-outs during heatwaves, partly because batteries, cooling systems, and tyres are all put under extra strain. That means a higher chance of seeing a broken-down vehicle, often in an awkward spot, with its hazards on. Watch for hazard lights and people standing near their cars, and pass with care.

Additional Hazards to Watch For

Beyond the road surface and other drivers, extreme heat brings a handful of hazards that are easy to overlook.

Sun glare and dazzle. Low sun, particularly during early morning or early evening journeys, can dazzle you significantly, especially on east–west roads. Keep sunglasses to hand, use your sun visor, and make sure your windscreen is clean inside and out — dirt and smears scatter light and make glare worse.

Heat haze. On very hot days, especially on long straight roads or motorways, you may notice a shimmering, wavy distortion in the distance. This is heat haze, caused by light bending through layers of air at different temperatures near the road surface. It can make it harder to judge the speed and distance of vehicles ahead, so if you notice it, build in a bit more following distance.

Windows-down hearing risk. It’s tempting to drive with all the windows fully down to get a breeze going, but at higher speeds this creates significant wind noise. Audiologists have warned that even relatively short periods of this can affect your hearing, and it can also mask the sound of horns, sirens, or hazards you’d normally hear. A small gap, or your air-con, is a safer way to stay cool.

Children, pets, and vulnerable passengers. Never leave anyone — child, elderly relative, or pet — alone in a parked car in hot weather, even briefly and even with windows cracked. Car interiors heat up extremely quickly and this can become fatal in a very short space of time.

Dehydration and heat-related illness. Long journeys in heavy heat can cause dehydration, dizziness, or even heat exhaustion, all of which impair your driving. Drink water regularly, take breaks on longer journeys, and if you start to feel unwell, find somewhere safe to stop rather than pushing on.

Hot brakes and clutches. Stop-start traffic in extreme heat puts extra strain on brakes and, in manual cars, on the clutch. If you’re a learner still getting used to clutch control, be aware that repeated heavy use in slow traffic can make things feel different (a slightly different biting point, more smell from the clutch) — this is normal under strain, but worth mentioning to your instructor if it feels excessive.

Infrastructure problems. In genuinely severe heat, there’s a slightly higher chance of disruptions such as power cuts affecting fuel stations or traffic signals, or issues with railways running parallel to roads. These are rare, but worth being aware of if you’re travelling during a red weather warning specifically.

A Quick Checklist Before You Drive in a Heatwave

• Check tyre pressure and condition when tyres are cold
• Check coolant and oil levels (engine cold)
• Top up windscreen washer fluid
• Confirm air-con is working, or plan ventilation if not
• Pack water, sunglasses, and a cool bag for drinks/snacks
• Travel outside peak heat hours where possible
• Watch for changes in the road surface, especially on smaller or older roads
• Give yourself extra following distance — for grip, for distracted drivers, and for heat haze
• Expect more cyclists, walkers, and motorcyclists than usual
• Never leave a child, elderly passenger, or pet alone in the car

The Bottom Line

Extreme heat asks more of your car, more of the road, and more of every driver around you. None of this means you should be nervous about driving in summer — but it does mean a bit of extra preparation and a bit of extra awareness go a long way. For learner drivers, building these checks into your routine now means they’ll simply become second nature, whatever the weather throws at you later in your driving life.

If you’re not sure how your car or your driving should adapt to the heat, it’s always worth raising it with your instructor on your next lesson — a few extra minutes talking through hot-weather habits could make a real difference on the road.

Hot weather can also affect your concentration and fitness to drive. Read my guide to checking whether you’re fit to drive.