Colorado, as many of us regularly brag to our out-of-state friends, has 300 days of sunshine. Those sunny days are one reason it’s a great state to enjoy outdoor activities such as hiking, biking, and skiing.

The one downside to these sunny days and outdoor activity opportunities is excessive exposure to the sun’s ultraviolet rays. Because of sun exposure at high altitudes, Colorado has the nation’s highest per-capita rate of skin cancer.

The good news is that you can reduce your risk of developing skin cancer without hiding inside all day, and it starts with how you protect your skin.

“Sunscreen is the best weapon we have against protecting our skin from ultraviolet radiation, which can lead to aging of the skin and skin cancer,” said Dr. Aly Barland, UCHealth dermatologist at the UCHealth Longmont Clinic.

The when, where and how of applying sunscreen to protect your skin

Whenever you’re outside, and your skin is exposed, whether it’s cloudy and cold or hot and sunny, you should wear sunscreen, said Barland. “There are always ultraviolet rays that your skin’s receiving.”

She recommends not only covering all exposed skin with sunscreen but also, in some cases, covering skin with clothing, especially if you’re playing sports or doing some sort of outdoor activity.

An ounce of sunscreen, about a shot-glass size of sunscreen, is the amount needed for your entire body. Be sure to apply it about 20 minutes before sun exposure so it has time to dry. And the best way to apply it is to squeeze some lotion onto your hands and rub it directly on your skin.

“Usually, a cream or lotion is more effective than a spray because you may not be directly applying [the sunscreen] to your skin since some of it is aerosolized. You get a more even layer of sunscreen when you use a cream or lotion and apply it with your hands.”

Dr. Rebekah Zaluzec, a plastic and reconstructive surgery expert at UCHealth Cherry Creek Medical Center, recommends broad Spectrum UV sunscreen which protects against UVA and UVB (two types of radiation).

“Start by applying first thing in the morning, and it is really important to reapply in the afternoon; reapplying is what people find the most challenging because we tend to forget, Zaluzec said.

Is mineral sunscreen or chemical sunscreen better?

The best sunscreen is the sunscreen that you use regularly. Whether it’s chemical sunscreen or mineral sunscreen, a spray sunscreen or sunscreen lotion, the type is not as important as the effort.

As for ingredients, Barland said, it’s a matter of preference when it comes to using a mineral sunscreen or a chemical sunscreen. For those with sensitive skin, or concerns about chemical ingredients, a mineral sunscreen would be the best sunscreen option. The only two mineral sunscreen ingredients available are zinc oxide and titanium dioxide. These ingredients sit on your skin as a shield against the sun’s ultraviolet rays. They are not absorbed into your skin or bloodstream.

Recent studies have found that chemical ingredients such as avobenzone and oxybenzone are absorbed into the skin and, subsequently, your bloodstream.  However, it’s not known at this time if those ingredients are harmful.

“We do not yet know the implications of chemical absorption and whether it is harmful,” said Barland. “We do know that skin cancer can be deadly. If people are hesitant about sunscreen use and these studies, they can stick to mineral sunscreens only.”

Is it necessary to reapply sunscreen?

Absolutely, it’s necessary to reapply sunscreen. Many people think that slathering on sunscreen once is fine. Not true. Sunscreen wears off, especially if you’re sweating or swimming. The general rule is to reapply every one to two hours if you’re going to be outside for a while, said Barland, because it becomes less effective over time and in the sun.

But, if you’re swimming, you should reapply as soon as you get out of the pool. “If you’ve been swimming or sweating, reapplying is important because water-resistant sunscreen is not waterproof, and it also washes off some in the water or with sweat.”

What SPF do I really need?

Barland recommends a sun protection factor, or SPF, of at least 30. SPF tells you how long the sun’s ultraviolet rays would take to cause damage to your skin. So, if you use an SPF 30 product, it would take 30 times longer to burn than if you weren’t wearing sunscreen.

The higher the SPF factor, the longer you’re protected, to a degree. For one, it’s only an accurate number if you apply the sunscreen as directed, meaning an ounce for your entire body and reapplying it regularly throughout the day.

“I generally recommend SPF 30 to 70. Beyond SPF 70, you’re probably not gaining much more in protective level,” said Barland.

For kids, do you need a children’s brand sunscreen?

Children under six months should not wear sunscreen. However, you should still protect them from the sun with protective clothing and shade. For children older than six months, any sunscreen will do. It does not need to be branded as a kids’ sunscreen.

Mineral sunscreen, though, may be a better option for children. “For kids older than six months, any sunscreen is fine. But we typically recommend sticking with a mineral sunscreen for kids because they tend to have more sensitive skin and mineral sunscreens are less irritating,” said Barland.

How else can I protect my skin from the sun?

In addition to sunscreen, you should wear a wide-brimmed hat, and sunglasses and limit sun exposure between 10 am and 4 pm when the sun’s rays are the strongest. These, and other sun protection guidelines, should be followed year-round.

“In the summer months when sunscreen is hard to reapply, wear UPF-rated clothing to cover the skin; wear long sleeves, etc., which can make consistency easier. Sometimes it may be hard to remember or keep up with sunscreen application, so this can be a great solution,” Zaluzec said.

Obviously, you don’t have to cover your body with sunscreen when you’re skiing. But, you should protect any exposed skin. “It’s important to remember that the sun is always present, no matter what season we’re in. You need to protect your skin throughout the year,” Barland said.