Driving Cool in a Heatwave

Rising temperatures in the summer months can not only affect your vehicle, but your own comfort and ability to drive.

Tip for drivers to keep cool in the Summer

Summer, the months from June to August, is the warmest and usually sunniest season. The UK also experiences the occasional heatwave, where the daily maximum temperature meets or exceeds the country’s threshold value for at least three consecutive days. When a heatwave hits, regardless of whether you’re going to be working in a hot cab, or are going away and driving your own vehicle on a long journey, these tips will help you prepare.

Before heading out

Rising temperatures can affect your brakes, tyres, engine oil and coolant. Take a few precautions before heading out:

  • Check your tyres – Check tyre pressures on your vehicle, especially if you’re planning to go on a long journey. Just like colder weather can cause PSI to drop, excessive heat can cause it to increase. Check for wear and tear as heat can wear down the tyre, the tread depth, and air pressure to avoid a blowout.
  • Brakes – Brakes can fail when temperatures get too hot as components can reach a point where they lose friction due to mass heat absorption. Check them frequently and if you’re carrying a heavy load with a long decent downhill, drop it down a gear to take some stress off the brakes.
  • Engine oil and coolant – Check your coolant level isn’t low as this can lead to overheating. Some oils may also be replaced in hot weather to a higher viscosity to help protect the engine in high temperatures.
  • Check the air-con works – If your vehicle has air-conditioning, you’re really going to want it in a heatwave! Book in a re-gas now so you’re confident you’ll reap the benefits of a cool car during hot weather.
  • Top up – If you’re going on a long journey and your cab is your home, invest in a mini fridge. Cool water, cans, or even ice-creams can be enjoyed during breaks. You could also freeze bottles of water and keep cooling sprays and handheld fan misters in the fridge, topping them up with chilled water just before you leave.
  • Expect longer trips – especially during the school holidays
  • Expect extreme weather – it can turn dramatically bringing thunderstorms, heavy downpours, flash flooding, thunder and lightning, and gale force winds


Whilst on the road

Always ensure you have enough water with you and take regular breaks. Driving in the summer months also means there is a greater risk of having your vision impaired by the sunlight, especially if you’re driving towards it. This can be distracting and may cause you to have longer reaction times to issues on the road. All drivers should make sure they have a pair of sunglasses, which will also protect eyes from harmful UV rays, on hand to keep their vision glare-free. Checklist:

  • Stay hydrated – Studies found that driving whilst dehydrated can be as dangerous as drink driving. They found that drivers under the influence of alcohol made the same number of mistakes as those who haven’t had enough water. Long journeys in a hot vehicle can lead to significant losses of water so it’s important to keep hydrated – and don’t put off drinking water to avoid toilet stops!
  • Wear appropriate clothing – Where permitted, try to wear cool clothes like smart shorts, short sleeved shirts or t-shirts to keep your body cool.
  • Keep cool when parked up – If you have to park up and wait for even just a short amount of time, it’s important to keep on the air-conditioning to regulate the temperature. The Department of Earth and Crime Sciences of San Francisco University carried out a study which took measurements every 10 minutes from an enclosed vehicle. After 10 minutes, temperatures rose 19 degrees Fahrenheit, after 20 minutes 29 degrees Fahrenheit and after one hour, it had risen 43 degrees Fahrenheit.
  • Wear a hat – Sun beaming through the windows can not only affect your vision, but also burn your head. Wearing a hat will block out the sun’s rays, keeping your head cool and block sunlight that could potentially impair your vision.
  • Wear sunglasses – Avoid glare with some sensible sunglasses. Remember, don’t wear glasses that have very dark tints as this can impair your vision and also land you with hefty fines. Category 4 lenses only transmit between 3% – 8% of light and should not be worn for driving, day or night. See the AA website for advice on driving in sunglasses.
  • You’re at risk of being sunburnt whilst behind the wheel, especially with your windows down so it’s important to wear sunscreen for skin protection.

Air conditioning vs open windows

There’s the old debate of whether air con is more expensive than driving with open windows. If you’re driving slowly, like you would through a town or built-up area, open windows will keep you cool. However, when you’re going faster, such as on a motorway, the wind resistance created by open windows will use more fuel than running on aircon.

Keep parked cabs cool

Delivery schedules may make this impossible, but if you can, try to avoid driving during the hottest part of the day and avoid parking in direct sunlight. If you have to park in the sun, use windscreen sunshades on your dashboard to reflect the sun’s heat.