Drivers Advised to Refuel Ahead of Scorching Temperatures
Motorists across the UK are being urged to fill up their vehicles with petrol or diesel before Wednesday, June 24, when temperatures are forecast to soar to 40°C in London and exceed 35-38°C across much of England and Wales, according to the Met Office. The forecaster has issued amber and red weather alerts covering most of the UK from Tuesday through Thursday.
The advice comes as hot weather conditions increase fuel consumption, potentially catching unprepared drivers off guard. With petrol averaging 154.72p per litre and diesel at 174.30p, according to the RAC, drivers are keen to avoid wasting fuel unnecessarily.
How Hot Weather Reduces Fuel Economy
According to the US Department of Energy, hot weather can initially improve fuel economy as engines warm up faster and summer gasoline has slightly more energy. However, the use of air conditioning (A/C) to stay comfortable significantly reduces fuel efficiency. The department states: "Under very hot conditions, A/C use can reduce a conventional vehicle's fuel economy by more than 25%, particularly on short trips." This effect is even larger for hybrids, plug-in hybrids, and electric vehicles.
Additionally, driver behaviors such as opening windows increase aerodynamic drag, further lowering fuel economy. The US Department of Energy notes: "Hot weather can increase fuel economy... however, keeping comfortable in hot weather by rolling down the windows or using the air conditioning can reduce fuel economy."
Risk of Running Out of Fuel in Hot Weather
Experts at PassMeFast.co.uk warn that fuel levels drop quicker than usual in warm weather, making it unreliable to rely on normal estimates. They advise: "To avoid getting stuck in the middle of nowhere, or at the centre of a traffic jam on a hot day (both nightmare scenarios), make sure you head to the petrol station in good time. Playing it close to the line is just not worth it if the sun's out!"
Debunking the Exploding Fuel Tank Myth
Some drivers have expressed concerns about filling up during hot weather due to a risk of explosion. However, RAC spokesperson Rod Dennis clarified: "There is no truth in this. All fuel systems on passenger vehicles are designed to cope with any expansion of fuel, or vapour coming from the fuel. There is no risk of explosion from filling up a fuel tank fully and drivers should have no concerns in doing so."
Optimal Temperature for Fuel Economy
Fuel Finder UK explains that the "sweet spot" for fuel economy is between 15°C and 20°C. At -5°C, efficiency drops by around 10% compared to 20°C, and for short trips under four miles, that penalty can reach 20% or more. However, once temperatures hit 32°C, engine efficiency is reduced and there is a risk of overheating, negating any gains.
Drivers are encouraged to plan ahead and refuel before the heatwave peaks, ensuring they have enough fuel for their journeys and avoiding the need for emergency stops in extreme conditions.
