Take refuge in some shade to avoid over-exposure to dangerous ultraviolet radiation coming from the sun. Your skin can be damaged in as little as 15 minutes.

Over the past three decades, many studies have proven that over-exposure to the sun may increase the risk of skin cancer — the most common form of cancer in the U.S. According to the Centers for Disease Control and Prevention, 61,646 people were diagnosed with melanomas of the skin and 9,199 people died from skin cancer in 2009 alone.

Most people understand that the sun is strongest between 10 a.m. and 4 p.m., but did you know the intensity of ultraviolet radiation is directly related to the angle of the sun and its altitude above the horizon?

Solar altitude varies with season and location on earth, so simply remember the shadow rule: when your shadow is shorter than you are tall, the intensity of ultraviolet radiation from the sun is more likely to cause sunburn. These are the perfect times to escape into some shade.

Source: Downham TF 2nd. The shadow rule: a simple method for sun protection. Southern Medical Journal. 1998.