As many as 60,000 people a year die from too much sun, warns the World Health Organization.
Sun damage can lead to deadly skin cancer
The bulk of the deaths are from skin cancers caused by excess exposure to the sun's harmful rays, ultraviolet radiation, says WHO.
UVR also causes sunburn, triggers cold sores and ages the skin, according to its report, the first to outline the global health burden of sun exposure.
Simple measures, such as covering up when in the sun, could cut the deaths.
Dr Maria Neira, Director for Public Health and the Environment at WHO, said: "We all need some sun, but too much sun can be dangerous - and even deadly.
"Fortunately, diseases from UV such as malignant melanomas, other skin cancers and cataracts are almost entirely preventable through simple protective measures."
Of the 60,000 deaths, 48,000 are caused by malignant melanomas and 12,000 by other skin cancers, the report Global Burden of Disease of Solar Ultraviolet Radiation estimates.
WAYS TO AVOID TOO MUCH SUN
Limit time in the midday sun
Wear protective clothing including hats and sunglasses
Use sunscreen of sun protection factor 15+
Avoid sunlamps and tanning parlours
Source: World Health Organization
More than 1.5 million "disability-adjusted life years" or DALYS - a measure of the loss of full functioning due to disease and death - are lost every year due to sun exposure, WHO believes.
WHO and the World Tourism Organization of the United Nations are urging people to be extra-vigilant when out in the sun to protect themselves from UVR
Everyone is exposed to UVR from the sun. Small amounts are beneficial to health, and play an essential role in the production of vitamin D by the skin. However, overexposure to UVR is associated with a variety of serious and deadly health problems.
UVR levels vary with the time of day and year. Levels are highest when the sun is higher in the sky, typically between 10am and 2pm.
Latitude and altitude also alter exposure. The closer to equatorial regions and the higher the altitude, the higher the UVR exposure.
Similarly, the ground you walk on can be important. Grass, soil and water reflect less than 10% of UVR, fresh snow reflects as much as 80%, dry beach sand about 15% and sea foam about 25%.
UVR can neither be seen nor felt, therefore, UVR measurements, such as the global solar UV index, are necessary to determine precisely the extent of ground level UVR. These add up all the solar UVR, taking account of its ability to cause skin damage.
The higher the UV index, the higher the risk of skin and eye damage. When the UV Index predicts radiation levels of 3 (moderate) or above, sun safety practices should be taken, WHO recommends.
Laura-Jane Armstrong, cancer information officer at Cancer Research UK, said: "This report provides clear evidence of the dangers of over-exposure to the sun, highlighting the number of global deaths from skin cancer and other risks the sun can pose to our health.
"Our key message is not to burn. To help protect yourself in the sun you should spend time in the shade during the middle of the day, cover up with a shirt and hat, and use factor 15+ sunscreen."