Four items drivers should NEVER leave inside their car in blazing sunshine as heatwave ‘likely' this weekend

The Sun

18-06-2025

MOTORISTS are being urged to think twice about what they leave behind in their vehicles, as forecasters warn that a heatwave is 'likely' to hit parts of the UK later this week.
With temperatures expected to climb to a scorching 34C in some areas, certain everyday items could pose serious risks if left in the car.
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In counties such as Surrey, where high temperatures are expected, drivers are being encouraged to clear their vehicles of particular items that may react dangerously to heat.
The Met Office defines a UK heatwave as a period of at least three consecutive days in which temperatures reach or exceed a specified threshold.
In the South East, including Surrey, Greater London, Buckinghamshire, and neighbouring counties, that threshold is 28C – the highest classification in the country.
While many motorists may already be planning ahead for warm weather, experts say that failing to remove common items from inside a parked car could result in damage, safety hazards, or even health risks.
The inside of a car can quickly become much hotter than the outside air, especially when parked in direct sunlight.
One item to be particularly wary of is bottled water.
Although staying hydrated is essential during hot weather, leaving plastic bottles in the car can be dangerous.
When plastic is exposed to intense heat, it can release harmful chemicals into the water, making it unsafe to drink.
What's more, if the bottle is left on a seat or dashboard, sunlight magnified through the bottle could potentially start a fire by focusing rays on flammable materials.
Another unexpected hazard is sun cream.
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While it's a must-have during sunny spells, the packaging of sun cream isn't designed to withstand extreme heat for prolonged periods.
Heat can cause the contents to expand, potentially bursting open and leaking onto seats or other surfaces, leaving difficult stains.
Beyond the mess, high temperatures can also degrade the ingredients in the cream, making it less effective at protecting your skin from UV rays.
Medicines are also at risk in sweltering conditions.
Many over-the-counter treatments, including common painkillers like paracetamol or ibuprofen, can lose their effectiveness if exposed to heat.
Although the tablets might look unchanged, their chemical structure could be compromised.
Medical professionals recommend that drivers always read the storage instructions included with any medication and avoid leaving them in a hot vehicle unless clearly stated otherwise.
Battery-powered electronics such as smartphones, tablets, laptops and even portable chargers should also be removed from the car during sunny weather.
These devices contain lithium-ion batteries which are sensitive to heat.
When exposed to temperatures above 40C – which can easily be reached inside a closed vehicle – batteries can malfunction, drain faster, or in rare cases, overheat to the point of catching fire.
Even if they don't ignite, long-term exposure to high temperatures can shorten a device's lifespan significantly.
There are other heat-sensitive items that drivers should avoid leaving behind.
Aerosol cans, for example, are extremely sensitive to heat and can explode when internal pressure builds up in high temperatures.
Items like make-up, particularly lipsticks and foundations, can melt and seep into seats or fabrics, leaving behind stubborn stains and strong smells.
Food should also be cleared from the car – not only because it can spoil quickly in the heat, but also because it can attract pests or leave unpleasant odours.
Plastic toys, particularly those left by children on back seats or dashboards, can also warp or emit fumes if left in the sun for too long.
These toys may not pose an immediate safety threat, but they can easily become deformed, sticky, or unusable after just a few hours in the heat.
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