RAC Cars News


The dangers of a hot car

By raccars Published

dog in car

We all know the dangers of leaving a dog or child in a hot car, but what else can go wrong?

The British obsession with our famously miserable weather means that we often underestimate the danger of a hot car on our rare sunny days. Annual campaigns warning drivers not to leave their dogs in hot cars are having some effect but emergency situations still occur. A car sitting in the sun can become an oven in a very short amount of time.

For example if the outside temperature is 22C, the temperature inside the vehicle can go up to 47C within an hour. Don't assume that all will be OK if you leave the windows a little ajar or park in the shade.

If you see a dog in hot car

The best thing to do is to call the RSPCA on 0300 1234 999. If the animal appears to be distressed or unwell and the RSPCA advise that they will not arrive quickly enough, you should call the police on 999. You may be tempted to smash a window to help the animal and you may receive public support for the action. However, you could potentially be charged with criminal damage and may even end up in court.

Where possible, allow the RSPCA or the police to take the necessary action. If you are forced to act yourself, make sure that you take pictures of the situation and the names and addresses of witnesses in case you need a defence later on.

The same applies to leaving children in hot cars. It's a bad idea, NEVER do it!

In addition to living beings, it's fairly obvious that there are some items it's not wise to leave baking in a car; cold groceries and electronic equipment such as mobile phones, for example. However there are some other, unexpected items which can be damaged by the heat.


We all know the wisdom of wearing sunscreen when outdoors in the summer months, and for convenience many people leave some sunscreen in the car so that there is always a bottle to hand if they forget to apply it at home. However, the heat can affect the sunscreen by degrading it and reducing its effectiveness. This means that your skin will be left without adequate protection from the sun's rays, and on a particularly hot day you could even find the plastic bottle melts in the heat, which is both messy and annoying.


Do not leave standard prescription lenses or sunglasses inside your car on a hot day. The heat can warp and soften plastic frames so that they will no longer fit and can even burn the skin when you put them on. This is even more likely with metal framed specs.


There is some concern that water can be unsafe to drink if it is contained within plastic bottles made of polyethylene terephthalate which have been left in a hot car. The theory is that this material, when heated, releases small amounts of BPA (bisphenol A) and antimony. The danger has yet to receive any official confirmation but it's best not to risk it.

Similarly, avoid leaving cans or bottles of fizzy drinks inside a hot car because the heat can cause the contents to expand and the containers to explode. Heat can also see corks popping out of bottles of wine and can change the taste of the wine when you drink it.


Most medication is designed to be effective at room temperature or in some cases to be refrigerated. The composition and effectiveness of some medications can be compromised if exposed to heat.

Wet swimming clothes

Wet swimwear is a haven for bacterial growth. People commonly wrap their wet swimwear in a towel before putting it in the car, and sometimes it even gets forgotten and left there when you get home. It's safer to make sure that swimwear is dry before you put it in the car.

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