Drivers are being urged to avoid washing their cars between 10am and 5pm as soaring temperatures are set to grip the UK on Thursday, with experts warning that cleaning vehicles during the hottest part of the day could do more harm than good. As another spell of hot weather arrives, many motorists may be tempted to give their cars a clean.
However, vehicle experts at BigWantsYourCar.com say the combination of intense sunshine and high surface temperatures can leave behind streaks, watermarks and even cause damage to a car’s paintwork. A spokesperson for BigWantsYourCar.com said: “Washing your car at the wrong time of day can lead to streaking, watermarks and even damage to the finish. In strong sunlight, water and car shampoo dry too quickly, often before you’ve had the chance to rinse them away properly, which can leave unsightly marks on the bodywork.”
Why Midday Washing is Harmful
The warning comes as temperatures are expected to climb during Thursday’s heatwave, creating what experts describe as a “danger zone” for washing vehicles during the middle of the day. When temperatures peak, water evaporates rapidly from the vehicle’s surface, making it difficult for cleaning products to lift dirt effectively. Instead of removing grime, soap and residue can dry onto the paintwork, leaving stubborn marks and reducing the effectiveness of the wash.
“It may seem like a good idea to wash your car while the sun is out,” the spokesperson added. “But intense heat actually works against you. Cleaning products can dry too fast and cause smears, while rapid evaporation makes it harder to rinse away dirt properly.”
Best Times to Wash Your Car
Instead, motorists are advised to wash their vehicles before 10am or after 5pm, when the sun is less intense and cooler conditions allow cleaning products to work properly. Experts have also warned against leaving car washing until after dark. “Avoid washing after sundown. You can’t see dirt clearly, and it becomes harder to dry the vehicle properly,” the spokesperson said. “Residual moisture left overnight can encourage corrosion or attract insects, which often stick to damp surfaces.”
Tips for Protecting Paintwork
For the best results, drivers are encouraged to wash their vehicles in a shaded area rather than in direct sunlight. A garage, covered carport or shaded driveway will help keep the car’s surface cool, giving shampoos, waxes and polishes enough time to work before drying out. “If you can, always wash your car in the shade,” the spokesperson said. “Sunlight accelerates drying, which ruins the cleaning process. Whether you’re using shampoo, polish or wax, you need enough time to work the product before it dries out. That’s only possible if the surface stays cool.”
With hot weather expected to continue, motorists are being encouraged to plan their car cleaning around cooler parts of the day to protect their vehicle’s paintwork and avoid unnecessary damage.
