Cancer Research UK says too much UV radiation from the sun or sunbeds can damage the DNA in skin cells. If the DNA builds up enough damage over time, it can cause cells to start growing out of control, leading to skin cancer.
There are two main types of UV rays. Both types can cause skin cancer - UVB and UVA.
Sunburn is a clear sign that the DNA in your skin cells has been damaged by too much UV radiation. Sunburn doesn’t have to be raw, peeling or blistering. If your skin has gone red in the sun, it’s burnt.
The above video, by Cancer Research UK, explains what happens to skin when it becomes sunburnt.
More top news
Emma Jesson brings you Saturday night's forecast
Feeling much colder later on Saturday. Wintry showers possible on Sunday and Monday
The pressure group Ashley Out has called for demonstrations outside every Sports Direct store within a 20-mile radius of St James' Park.