Sun’s out? Here’s what the UV index says about your skin’s risk

London enjoyed highs of 18°C over the weekend of April 5-6, with warmer weather on the way.

As the days grow longer and summer in the capital draws nearer, there’s no better time to get outside and soak up the sunshine — a rare treat in the UK.

But just because our summers aren’t scorching doesn’t mean you can skimp on sun protection.

Sunburn isn’t just painful in the short term — it also increases your risk of skin cancer and can accelerate signs of ageing, leaving skin less smooth and more prone to wrinkles.

Here’s what you need to know to stay safe in the sun this summer.

What is the UV index and how high does it go?

The UV index — short for ultraviolet index — is an international standard that measures the strength of the sun’s UV radiation at a particular place and time.

UV rays cause sunburn, so the index helpfully indicates how harmful the sun could be to your skin on any given day.

The scale typically runs from 0 upwards:

A UV index of 1–2 is considered low risk for most people.
An index of 3 or above can start to damage some skin types, particularly fair skin, so Sun protection is recommended.
A reading above 6 means extra caution is needed, especially around midday.
Anything over 8 is considered very high risk — it’s best to seek shade and avoid direct sunlight during peak hours.

The UV index is usually highest between 11am and 3pm, especially in summer, and can be influenced by factors such as altitude, cloud cover and reflective surfaces such as water or sand.

Keeping an eye on the daily UV forecast can help you decide when to apply sunscreen, wear a hat, or stay in the shade.”

How to stay safe in the sun

Symptoms of sunburn often don’t appear until around four hours after the damage is done, so don’t wait until you feel heat or pain to take action.

The best way to stay safe is to be proactive — avoid prolonged exposure to direct sunlight when possible, especially during peak hours (usually 11am to 3pm).

Always wear sunscreen with at least sun protection factor (SPF) 15, and remember to reapply it every two hours, or immediately after swimming or sweating.