A driver's guide to staying safe during hot weather

Driving safely starts before you leave

Hot weather bring a unique set of challenges for motorists that go well beyond switching on the air conditioning. Vehicle components work harder, passengers are more vulnerable to heat, visibility can be affected by sun glare, and hosepipe bans can leave drivers unsure how to clean their cars (legally). 

In this guide, we share what every driver should know before setting off on their journey, including practical tips on staying safe, keeping cool, and looking after their vehicle during heatwaves.

How can drivers wash their cars despite a hose pipe ban? 💦

Drivers may still use a bucket, sponge, watering can or collected water that hasn't come directly from the mains, but they should use it sparingly and check the exact rules with their own water supplier before washing the car at home. 

The key thing is to be sensible about what actually needs cleaning. In hot, dry weather, dust, pollen, bird mess, and road grime can build up quickly, and it's the safety critical areas drivers should prioritise first. Windscreens, mirrors, lights, and number plates all need to be kept clear, especially when low sun or glare can already make visibility more difficult. 

Using a hosepipe when restrictions are in place can lead to a fine of up to £1,000, but driving with poor visibility or an unreadable number plate can also land motorists in trouble. A dirty windscreen, smeared glass or obscured lights can make it much harder to react quickly, particularly in bright sun, so a targeted clean is often the safest and most water-conscious option.

How can people keep cool in their car without air con? ❄️

If your car doesn't have air conditioning, or you're trying to use it less, the best thing you can do is stop the car getting unbearably hot before the journey starts. Park in the shade where possible, use a windscreen shade, and open the doors or windows for a short time before setting off to let the trapped hot air escape. 

One simple trick is to create cross-ventilation through the car before setting off. Opening a front door and the opposite rear door several times can help force trapped hot air out much faster than opening a single window, helping cool the inside of the vehicle before passengers get in. For drivers who regularly travel in warm weather without air conditioning, a small USB-powered fan can also help improve airflow around the vehicle and make the inside feel more comfortable during longer journeys. 

Once you're moving, opening the windows can help at lower speeds, particularly around town or in slow traffic. On faster roads, drivers may need to be more practical, as open windows can create wind noise and drag, but even small changes like wearing loose, light clothing, keeping cold water in the car, and planning breaks can make a long journey much more manageable.

What are the health dangers of being in a car in hot weather for too long? 🌡️

Cars can act like greenhouses in hot weather, and the danger is how quickly the temperature can rise. When outside temperatures climb above 30°C, the inside of a parked car can exceed 60°C within minutes, which can create dangerous conditions for children, pets and vulnerable passengers in under 10 minutes.

That's why 'just five minutes' should never be treated as harmless. A quick stop to pay for fuel, collect something, or pop into a shop can still become risky, especially if someone is left waiting in a parked vehicle. Cracking a window or parking in partial shade is not something drivers should rely on, because heat can still build quickly and shade can move. 

Babies, young children, older people, pets, and anyone with certain health conditions are especially vulnerable because they may struggle to regulate their body temperature or communicate that they're becoming unwell. In people, warning signs can include dizziness, headaches, nausea, heavy sweating, cramps, confusion, unusual sleepiness or becoming very quiet. With pets, signs can include heavy panting, drooling, restlessness, vomiting, weakness or collapse. 

By the time those signs are obvious, the situation may already be urgent. The safest approach is to avoid waiting in a parked car during hot weather wherever possible, and never leave children or pets unattended in the vehicle. 

It's not just the air temperature drivers need to think about. It's also worth checking the inside of the car before passengers get in. Steering wheels, metal seatbelt buckles, leather seats, and child seat fittings can become painfully hot when a car has been parked in direct sun. Electronics, medication, aerosol cans, and plastic bottles can also be affected by extreme heat, so drivers should avoid leaving heat-sensitive items in the car where possible.

When is the most dangerous time to drive during the summer? 🕐

There's not one single dangerous time that applies to every driver, but the middle of the day into the afternoon is often when heat, tiredness, and pressure on the car can build. The interior may already be hot before the journey begins, road surfaces are warmer, and long queues or slow-moving traffic can make the heat feel even more intense.

Early morning and late afternoon bring a different risk, because the sun is lower in the sky and can cause sudden glare through the windscreen. If the glass is dirty, smeared or low on screen wash, visibility can change very quickly, which is why keeping the windscreen clean is particularly important during summer. 

Hot weather can also be hard on the vehicle itself. Previous heatwaves have seen breakdowns rise by around 20% when temperatures exceed 30°C, and the heat can put extra pressure on tyres, batteries and cooling systems. Before setting off on a longer journey, drivers should check coolant, tyres, screen wash, and fuel or charge levels, and avoid pushing on if warning lights, unusual smells, steam or smoke appear.

Lesser-known hot weather driving risks drivers often overlook 🚗

Some of the biggest summer driving risks are the ones motorists don't always connect with heat. Low coolant is an obvious concern, but high temperatures can also make existing tyre damage worse, speed up wear inside the battery, and make weak air conditioning systems more noticeable just when drivers need them most. 

Tyres should be checked before motorway journeys or trips with a fully loaded car. Heat causes the air inside tyres to expand, and if a tyre is already underinflated, cracked, worn or damaged, the extra heat from the road surface can increase the risk of a puncture or even a blowout. A replacement tyre can cost around £80 to £250, so checking pressures when the tyres are cold is a simple habit that can help reduce both safety risks and unexpected costs. 

Battery problems are often associated with winter, but extreme heat can be just as damaging. High temperatures can speed up wear inside the battery and cause battery fluid to evaporate more quickly, making failure more likely. If the car is slow to start, dashboard lights appear dim or electrical features seem weaker than usual, it's worth getting the battery checked before a long journey. Replacing a failed battery can typically cost between £120 and £300. 

Drivers should also be careful with what they leave in the car. Medication, aerosols, phones, tablets, plastic bottles, and other heat-sensitive items can all be affected by high temperatures. It's easy to focus only on the driver and the engine, but in very hot weather, the whole car needs to be treated as a heat risk. 

 

The safest summer habit is to check the vehicle, the driver and the passengers before setting off. If the car is struggling, visibility is poor, or anyone inside is getting too hot, it's better to stop, cool down, and reassess than try to continue the journey.