Items you shouldn't leave in a car in high temperatures

By Chris Norman
on July 23, 2019 9:41:34 AM BST

Items you shouldn't leave in a car in high temperatures

By Chris Norman
on July 23, 2019 9:41:34 AM BST


Some reminders of what to watch out for in the high heat

Despite cars being considered a seemingly convenient storage place, think carefully about what you keep in your car especially when many of these ‘harmless’ items could be detrimental to your safety.

How quickly does the interior of a car heat up?

Believe it or not, it doesn’t take very high temperatures for the interior of a car to become very hot as cars rapidly experience the greenhouse effect due to sunlight and air confinement. The greenhouse effect occurs when the sun’s energy enters the car and starts heating up solid objects, like the seats and dashboard, which then radiate heat that gets trapped in the car.

Outdoor temperatures can be as low as 16°C, but a car interior can easily reach 38°C and an outdoor temperature of 30°C could lead to an interior temperature of 60°C. The Stanford University School of Medicine carried out a study which showed that the vast majority in the average temperature increase occurs within a half hour after a car is parked. 

Below are some examples of things you should not leave behind after parking your car in warm temperatures.

Plastic Bottles

Warping and melting are not the only effects heat can have on plastic bottles. When plastic overheats, harmful chemicals can be released into the liquid inside. The NHS has published information warning about the common chemical found in plastic water containers, Bisphenol A (BPA). BPA is thought to possibly interfere with sex hormones, which could affect puberty, menopause, or even cause hormone-related cancers.


Lighters are extremely dangerous to have in a vehicle due to them being able to explode in high temperatures. This could damage the glass inside the vehicle and burn holes in the seats.

Lotions and Medication

It is best to avoid leaving any medication or lotions in a hot car. When these products are exposed to hot temperatures, their shelf life can be shortened in addition to their chemical composition being altered.

Battery-powered Electronics

Never leave any power banks or lithium ion-powered devices in the car. High temperatures can cause irreversible damage and combustion to electronic devices.

Heat is also the worst enemy of all electronic gadgets including laptops, smartphones and even e-cigarettes. Leaving your smartphone for more than about two hours in a hot car can permanently shorten the battery’s life and damage other hardware parts, causing irreversible damage.


Believe it or not, when wine bottles overheat, the flavour could be affected, as well as the liquid expanding to the extent that it can push the cork out.


Many people don’t know that the active ingredients in sunscreen break down in high heat. So, if it is left inside the car, not only could its effectiveness be reduced, but it could actually explode – leaving behind a horrible sticky mess.

Pet Food

Animal food will change composition when exposed to high temperatures just like human food, potentially causing food poisoning for your furry friends.

Although it is common knowledge that kids and pets should not be left in the car during the warmer months, many people are unaware of the consequences of committing these acts, as well as what to do when they are witness to one.


The law doesn’t indicate an age when a child can be left on their own in a car, but it is still an offence to leave a child alone if it places them at risk. The National Society for the Prevention of Cruelty to Children (NSPCC) says: children under 12 are rarely mature enough to be left alone for a long period of time; in addition to that, babies, toddlers and very young children should never be left alone. Parents can and will be prosecuted if they leave a child unsupervised ‘in a manner likely to cause unnecessary suffering or injury to health’.

It’s hard to believe that a parent would leave their child in these conditions, but as recently as June 2019, a toddler had to be rescued from a car park in Essex after being left alone in the vehicle for over an hour in 25 degree heat.

If ever encountering a distressed child in a vehicle, call 999 immediately.


Summer temperatures pose a serious threat to pets with owners facing severe punishments if something happens to their animal after it is left alone in the car. A pet owner could be charged with animal cruelty, and receive a criminal record, if a pet becomes ill or dies after being left unattended in a vehicle.

For those who don’t know, an animal cruelty charge carries a potential six month prison sentence and an unlimited fine. If faced with the situation of seeing a pet in distress confined inside a vehicle, call the police and ask for their assistance.




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