Lichtenfeld said that each year more than 2 million Americans are diagnosed with skin cancers, the great majority of which are classified as basal or squamous cell skin cancers. His organization estimates that in 2012, 76,250 Americans will be diagnosed with the most deadly form of skin cancer, invasive melanoma, which is more likely to spread than other skin cancers if not detected early. They estimate that in the U.S., 9,180 deaths due to skin cancer will occur this year, most from melanoma.

Litchfield added that sunscreen is not the primary protection people should rely on, and it is often applied improperly or depended on too heavily. He recommends using sunscreen with a sun protection factor, or SPF, of 30 and applying it repeatedly, along with other important barriers such as sun-protective clothing, hats and sunglasses.

Those measures can lessen the impact of excess sun, but sunburns are not the only indicator of sun damage, noted dermatologist Dina Strachan. She developed freckles on her hand soon after moving to the Los Angeles area, and knew the freckles’ significance: sun-induced skin damage.

“It wasn’t like I was out there trying to get a tan. I put sunscreen on my face every day,” said Strachan.

“There can be benefits to being outdoors in the sun, but you don’t want to deliberately tan. Tan skin is a danger signal the skin is being harmed,” Lichtenfeld said in an email.

Sun exposure triggers the production of melanin in the skin, but the resulting tan only partially shields the skin against further damage from the sun’s ultraviolet rays, Vilma Cokkinides, strategic director of Risk Factor Surveillance at the American Cancer Society, wrote in an email.

Health care providers acknowledge that there are some benefits to sun exposure. One of the most talked-about benefits is vitamin D, which forms when ultraviolet rays penetrate the skin, triggering a chain of events in the body that involves the liver and kidneys. Vitamin D is critical to bones, among other things. But the risks of exposure outweigh the benefits.

Carol Drucker, a dermatologist at The University of Texas MD Anderson Cancer Center in Houston, said that most people need 600 international units of vitamin D a day, and food and supplements are the safest way to add it. A 3-ounce serving of salmon, for instance, provides 447 IUs, and an 8-ounce serving of vitamin D-fortified milk provides 120 IUs, she said.

“We know that the sun is a carcinogen. There’s no sense to let sun protection go by the wayside in quest of vitamin D,” Drucker said.

While skin often is the focus when it comes to the sun’s impact on the body, eyes also may be a concern.

Richard Bensinger, an ophthalmologist at Swedish Medical Center in Seattle, said that sunlight is critical to the development and function of eyesight and not normally a threat to eye health. While it is possible to sunburn an eye, it is rare. Sunlight can affect cataract development and macular degeneration, but in day-to-day life the sun is not generally a high risk factor for eye damage.

“Ordinary sunglasses are perfectly fine,” Bensinger said. “The best thing you can do for any kind of health in bright sun is wear adequate sunscreen and wear sunglasses.”

Charles Crutchfield III, a dermatologist based in St. Paul and professor at the University of Minnesota Medical School, favors a pragmatic approach to sun exposure.

“I’m a realist, and I have to have credibility with my patients,” said Crutchfield, who believes telling them to avoid midday sun while on vacation is unrealistic.

“There are many benefits to sun, but you just need to enjoy it responsibly,” added Crutchfield, who noted that the sun may play a role in alleviating Seasonal Affective Disorder and may have other unidentified benefits. He suggested that if individuals are “sun smart,” use protection and avoid tanning and burning it’s acceptable to “go out and have lots of fun in the sun.”

“We were not meant to be mole people,” Crutchfield said.

Patricia Quigley is an award-winning journalist who has written for local, regional, national and international media.