Drivers are being urged to remove bottles of sun cream from their cars before Tuesday, when temperatures are forecast to rise.
The Met Office forecast says a high pressure weather system will build from the west from Tuesday, July 8, bringing dry and sunny conditions to southern parts of the UK. The weather is expected to be rainier and cloudier in the north, but drier and brighter spells are also on the cards, with temperatures set to rise throughout the week. The national forecaster says heat and humidity levels will gradually increase to give way to another period of hot weather by next weekend, with highs of 30C lasting into the following week.
In London, temperatures are forecast to be a warm 25C on Tuesday and will continue to rise into the weekend reaching 30C on both Thursday, July 10, and Saturday, July 9. With the warmer weather expected to arrive from Tuesday onwards in parts of the UK, drivers should ensure that bottles of sun cream are removed from inside their cars before then.
While it’s always a good idea to have sun cream on hand for when you’re out and about, leaving bottles inside cars when the weather is hot is not recommended as it can degrade the active ingredients that protect against harmful UV rays. As such, this makes the sun cream less effective at filtering out UV rays and so your skin’s level of protection from the sun is reduced.
High temperatures can also cause sun cream to separate and turn watery, making it more difficult to evenly apply, which again reduces its effectiveness.
Motorist Thailand explains: “Leaving sunscreen (sun cream) in a hot car, especially during summer, can cause changes in its composition. Most sunscreens are designed to remain stable at normal temperatures, but prolonged exposure to heat can:
“Break down active ingredients – sunscreens contain chemicals like avobenzone, oxybenzone, or zinc oxide, which may lose effectiveness when exposed to high temperatures. This means they might not provide full protection against UV rays.
“Change texture – heat can cause sunscreen to become watery, clumpy, or separated. If it looks different than usual, it may not spread evenly on your skin, reducing its effectiveness. Shorten shelf life – high temperatures can make sunscreen expire faster than expected, making it less reliable.”
Car retailer Dick Lovett says if you keep an emergency cosmetics bag in your car which contains sun cream, the best thing to do is to rotate the products in your bag regularly and to avoid leaving them inside your car for long periods.
It adds: “Makeup and skincare items often contain active ingredients or oils that can separate and degrade in high temperatures.
“One of the most important skincare products to have in summer is sun protection, but does that mean you can leave sunscreen in the car? No. SPF can lose its effectiveness when exposed to high temperatures, leaving you at high risk of burning. Retinol-based skincare can also become unstable, leading to skin irritation or it simply not working.
“If you store an emergency cosmetics bag in your car, you should rotate products regularly and avoid leaving them for long periods of time in the summer.”