With Memorial Day kicking off the unofficial start of summer, dermatologists tell News 12 there are three steps people can do to prevent from developing skin cancer.

Experts say the No. 1 thing people to need to know that is moisturizers that contain SPF is not enough to protect people from UV ray and sun exposure.

"The combination of the lotion and the sunscreen changes the chemistry of the sunscreen, it can make it less effective. If you're going to put a lotion, put that first and then a true sunscreen on top," says Dr. Gail Whitman of SkinCare Physicians.

Dr. Whitman says just one day in the sun without sunscreen and one bad sun burn, can cause deep damage.

"Blistering sunburns are the worst in terms of damaging the cells but any cumulative, any color change is damage to the cells. So, they can turn cells cancerous," says Whitman.

When it comes to applying sunscreen, timing is everything.

"A lot of people – you see them slathering it on and then going into the water and it doesn't even attach to the skin. So, I think people don't realize you should put it on a good half hour before you go out," says Whitman.