Drivers of petrol and diesel vehicles are being advised to fill their tanks before Friday, as the return of hot weather conditions this weekend could lead to increased fuel consumption and catch unsuspecting motorists off guard. The Met Office forecasts temperatures soaring to 30°C in London on Friday, April 24, climbing further to 31°C by Monday. Heatwave conditions may arrive as early as Saturday in parts of southern England, though some areas will experience rain and thunderstorms.
How Hot Weather Affects Fuel Economy
Hot weather poses an unexpected risk to your fuel tank. During high temperatures, petrol and diesel deplete more quickly due to driver behavior and reduced fuel economy. The US Department of Energy explains that while hot weather can improve engine warm-up and reduce aerodynamic drag, using air conditioning or rolling down windows significantly lowers fuel efficiency. Under very hot conditions, A/C use can reduce a conventional vehicle's fuel economy by more than 25%, especially on short trips. The effect is even more pronounced in hybrids, plug-in hybrids, and electric vehicles.
Fuel Gauge Inaccuracy
Your fuel gauge may become inaccurate in hot weather, providing a false reading of remaining fuel. Experts at PassMeFast.co.uk warn that fuel levels drop quicker than usual, so drivers should not rely on normal estimates. To avoid getting stranded in traffic or remote areas, it is wise to refuel early. Playing it close to the line is not worth the risk when the sun is out.
Myth of Explosion Risk
Contrary to some myths, there is no danger of your vehicle exploding from filling the tank in hot weather. RAC spokesperson Rod Dennis confirms: “All fuel systems on passenger vehicles are designed to cope with any expansion of fuel or vapour. There is no risk of explosion.”
Optimal Temperature for Fuel Economy
According to Fuel Finder UK, the sweet spot for fuel economy is between 15°C and 20°C. At -5°C, efficiency drops by around 10%, and for short trips under four miles, the penalty can exceed 20%. However, once temperatures hit 32°C, engine efficiency declines and overheating becomes a risk.
With current petrol prices averaging 154.72p per litre and diesel at 174.30p, according to the RAC, drivers will want to avoid wasting fuel. Filling up before the heatwave can help save money and prevent inconvenience.
