Warmer weather and longer days are here, encouraging people to get outside and enjoy some fun in the sun. But before you head out for that beach vacation, Memorial Day picnic or stroll in the park, it's important to remember a few simple precautions that can help protect you from the health dangers of sun exposure.

According to the Centers for Disease Control and Prevention, the sun's ultraviolet rays can damage skin in as little as 15 minutes, and excessive exposure can lead to skin cancer, the most common form of cancer in the United States.

Each year, more than 3.5 million cases of basal and squamous cell skin cancer, and 76,600 cases of melanoma -- the most serious type of skin cancer -- are diagnosed, according to the American Cancer Society.

That's more than the combined incidences of breast, prostate, lung and colon cancers. About one in five Americans will develop skin cancer.

According to the National Cancer Institute, there were on average more than 7,300 new cases of melanoma each year in California between 2006 and 2010, for a rate of 20.6 per 100,000 Californians, slightly worse than the national rate of 19 per 100,000 people.

Anyone can develop skin cancer, but some people face greater risk than others, including those who have a history of sunburns, frequent sun exposure, or fair skin or skin that burns, freckles or reddens easily. Those with blue or green eyes and those with blond or red hair are also generally more at risk. Anyone who has had skin cancer in the past or has a family history of skin cancer is at increased risk.

Fortunately, when caught early, skin cancer has a 98 percent cure rate, according to the American Academy of Dermatology.

Get in the habit of performing regular, head-to-toe examinations for signs of skin cancer, such as any new growths, sores that won't heal, or a mole that has changed. When checking your skin, look for the A-B-C-D-Es:

  • Asymmetrical. Does the spot or mole have an irregular shape?

  • Border. Does it have an irregular or jagged border?

  • Color. Does it have an uneven color?

  • Diameter. Is it larger than the size of a pea?

  • Evolving. Has it changed during the past weeks or months?

    If you notice any changes in your skin, or detect moles or spots that exhibit the A-B-C-D-E characteristics, contact your physician.

    In addition, there are some simple steps you can take to protect yourself from the sun and help prevent skin cancer, such as:

  • Stay in the shade, especially during midday hours (10 a.m. to 4 p.m.) when UV rays are strongest. Keep in mind that UV rays can reach you even on cloudy days and can reflect off surfaces like water, cement, sand and snow.

  • Wear clothing that covers your skin, including a hat with a wide brim.

  • Wear sunglasses that wrap around and block both UVA and UVB rays.

  • Use sunscreen with broad spectrum -- UVA and UVB -- protection and SPF of 30 or higher, and remember to reapply every two hours and after swimming, sweating or toweling off.

  • Avoid indoor tanning and sunlamps.

  • Be especially vigilant about sun exposure for infants and children. Their skin is thinner and more sensitive, so even a short time in the midday sun can result in serious burns.

    Enjoy your time outdoors this summer and remember to protect yourself and your family from the sun's harmful rays.

    James Korkos, M.D., is market medical director of the Concord-based UnitedHealthcare of California.