Be careful out there: 5 sun safety tips

"The main reason that people still burn when they have sunscreen on is they don't use enough and they don't use the right amount," Deb Girard, executive director of the melanoma group, said in an interview. "That's an ounce of sunscreen to cover your body if you're on a beach."

Dana-Farber suggests checking the expiration date on that sunscreen in your beach bag from last summer.

"In general, we recommend that you change your bottle of sun block yearly," Dr. Stephen Hodi, clinical director of the melanoma program said in a statement issued by Dana-Farber.

Girard concedes that long sleeves and pants might be a hard sell when the weather warms up, but she got a preview of the season's first sunburns when she took a cruise vacation last week. Pale people were sitting around the pool trying to tan. At the airport going home she saw a teenager who could barely walk from what Girard guessed were second-degree burns on her legs from too much sun.

"I thought, this is just crazy," she said.

A person's risk of skin cancer doubles if they have 5 or more sunburns and one blistering, really bad sunburn during childhood more than doubles the chance of developing melanoma later in life. The foundation tells teenagers if they want a tan, they should use a spray.

"Don't let yourself fry in UV rays," Girard said.