Devriez-vous porter de la crème solaire même lorsqu'il est nuageux ?

Should you wear sunscreen every day?

It's easy to assume that if it's not sunny outside then you don't need sunscreen - after all, you're not feeling the sun on your skin. But actually, you can still get sunburnt even when it's overcast and grey outside. It's the UV index that puts you at risk of burning, and that exists whether its bright and sunny or cloudy.

According to Dr Walayat Hussain of the British Association of Dermatologists (BAD), rather than relying on what the weather looks like - or the temperature - when deciding if you need sunscreen, you should be looking at the local UV forecast.

"If the UV index is three or higher, you should be protecting your skin,” he explains. "Your first line of defence should always be making use of shade, particularly between 11 am and 3 pm, wearing protective clothing, and applying a sunscreen with a minimum 4-star UVA rating and an SPF of 30 or higher."

Why is UV dangerous for your skin?

Any time your skin is exposed to harmful UV rays you have a chance of getting sunburn, which not only causes aesthetic damage to your skin, such as wrinkles, but also makes you more likely to get cancer de la peau.

Every time your skin gets damaged by the sun it can cause mutations in your cells, which can lead to malignant tumours.

Hussain explains that the UV index is generally higher on cloudless, hot days. However, UV rays can still get through when it is completely overcast. Although you are not more likely to get sunburnt when it's overcast, there is the danger of being lulled into a false sense of security when it is not obviously sunny.

"This can lead to sunburn on cloudy, cooler days - in spring as well as summer," he says. "In the winter months, UV protection in the UK is unlikely to be necessary except in people who are abnormally sensitive to sunlight."

UVA rays account for up to 95% of UV radiation reaching the Earth's surface, according to the Skin Cancer Foundation. UVA penetrates the inner layer of the skin, called the dermis, and UVB mainly affects the outer layer of the skin, called the epidermis. Both can cause cancer.

How can you protect yourself against sun damage?

"UVA is associated with causing premature skin ageing, whereas UVB is most responsible for causing sunburn. Both types of UV ray can cause skin cancer," Hussain adds.

"When choosing a sunscreen, it's important to choose one with both a high UVA rating and a high SPF, to ensure you're protected from both UVA and UVB rays."

Your likelihood of burning also depends on how long you'll be outside for.

If you work outside, or are planning on being outdoors all day, then you'll need more protection than someone who is just going for a quick walk. But you should always opt for a sunscreen with an SPF of 30 or more, and adequate UVA protection.

Is the SPF in a moisturiser enough?

Certains moisturisers and makeup provide an SPF, but don't presume it's enough if you're outside all day.

You need to make sure every area of your skin exposed to the sun, or not covered by clothing, is protected with sunscreen.

"SPF moisturisers and foundation can provide adequate protection if you're not planning to be outside for long periods - for example, if you're just popping to the shops at lunchtime," Hussain points out.

"However, if you intend to spend time outdoors, particularly in the summer months, sunscreens are much more effective, not least because they tend to be applied much more thickly."

Skin cancer

Skin cancer is one of the most common cancers in the world.

In the UK, more than 150,000 new cases of non-melanoma skin cancer are diagnosed each year.¹ It affects more men than women and is more common in the elderly.

Around 19,000 new cases of melanoma, the deadlier type of skin cancer, are diagnosed each year.²

Skin cancer can occur anywhere on the body, with most cases diagnosed in people under 50. Around 2,600 people die from melanoma each year in the UK.²