Causes

Sunburn is caused by too much exposure to ultraviolet (UV) light. UV light may be from sunlight or artificial sources, such as sunlamps and tanning beds.

Melanin is the dark pigment in the skin's outer layer that gives skin its normal color. When you're exposed to UV light, your body protects itself by producing melanin faster. The extra melanin creates tan. A suntan is the body's way of blocking UV rays to prevent sunburn. But the protection only goes so far. Too much UV light causes skin to burn.

You can get sunburn on cool or cloudy days. Snow, sand, water and other surfaces can reflect UV rays that cause the skin to burn too.