Summer unofficially kicks off each Memorial Day weekend, as our first real chance to head outdoors and enjoy the warmth and sunshine. “Don’t Fry Day” is an annual reminder, led by the National Council on Skin Cancer Prevention, to practice sun safety and be mindful of how the sun’s ultraviolet (UV) radiation affects us.

The effects of exposure to UV rays accumulate over your lifetime. Overexposure to this radiation is linked to skin cancer, which remains the most common form of cancer in the United States, and the rates are rising.

Nancy Akerman is a physical scientist and UV expert at the Environmental Protection Agency, and she conducts outreach and education on UV radiation and sun safety. She was kind enough to answer our questions.

The UV Index is celebrating its 25th birthday this year! What does it tell us? Please define its levels (or tiers) and related preventive actions so that people know what to do. Also, I hear the EPA has an app to monitor UV.

Yes, the UV Index is 25 this year, and EPA’s UV Index app is celebrating its 10th birthday! The UV Index is a forecast of the sun’s UV intensity and the expected risk of overexposure to the sun. The UV Index is reported on a scale from 0 to 11+, where 0 is no UV (nighttime) and the higher the number gets, the higher the risk you are at of harm from UV exposure. There are three categories of risk:

EPA’s free UV Index smartphone app, which is brought to you by EPA, the National Weather Service and the Centers for Disease Control and Prevention, is a helpful tool for planning your outdoor activities.

You can check the daily and hourly UV forecast for your location just by typing in your Zip code or having the GPS locator on your phone plug it in for you. It provides tips customized to the UV Index forecast for your location but reminds us that when the UV Index is high to try to seek shade when outside and cover up appropriately.

We updated the app this year so the UV Index app is now available in Spanish. You can search for “EPA’s UV Index” in the Apple app store and on GooglePlay. You can also check the UV Index online at

So the higher the UV index, the more we need to exercise sun safety for skin and eyes. What should we do, depending on the UV index’s different levels? Feel free to give us your favorite tips.

By reducing your exposure to UV rays, you can decrease your chances of developing skin cancer, cataracts and other eye damage.

Our favorite tip is to stay safe in the sun by remembering to SLIP, SLOP, SLAP and WRAP:

SLIP on long-sleeved shirts and clothes that protect your skin from the sun.

SLOP on a broad spectrum SPF 15+ sunscreen and reapply often.

SLAP on a wide-brimmed hat.

WRAP on a pair of sunglasses. Sunglasses that wrap around your face provide better protection from UV rays.

Another good rule of thumb is that you should seek shade whenever your shadow is shorter than you, and cover up and wear sunglasses. If possible, you should try to seek shade when you’re outside between 10 a.m. and 4 p.m., when UV rays are at their strongest.

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Does the weather influence UV levels? Any other factors we should keep in mind? I’ve noticed UV can still be very high on a cool day in April, so temperature isn’t a factor.

You’re right, temperature isn’t a factor, but the weather can be. A lot of people think that if it’s hot outside, the UV Index must be high, and if it’s cold, the UV Index is low. That’s not true — the UV Index can be higher in the winter on a clear, sunny day than it is on a hot day in the summer. That’s because the UV Index takes into account cloud coverage and elevation, among other factors.

It’s important we talk to people who don’t get sunburns easily or often. Are they immune to UV-related issues?

It’s true that people who get sunburned easily are at greater risk for developing skin cancer, but there are other genetic factors that can also increase your risk such as the presence of many moles or a family history of skin cancer. Regardless of how easily you burn, though, UV overexposure increases everyone’s likelihood of developing cataracts and other eye damage.

Is there any “safe” level of UV that I can receive, without raising my risk of skin cancer?

We recommend that you always take precautions to stay safe whenever you go outdoors, because damage caused by UV overexposure is cumulative over your lifetime. You only have one skin, so take care of it!

Do you recommend any particular types of sunscreen or sunglasses? When boating, sweating or on the beach, do we need to reapply some of these newer “physical” sunscreens as often?

We say “WRAP on a pair of sunglasses,” in Slip, Slop, Slap and Wrap, because sunglasses that wrap around your face provide more coverage for your eyes and therefore better protection from UV rays.

We recommend using any sunscreen that provides broad spectrum coverage, meaning it protects against both UV-A and UV-B rays, that has an SPF of 15 or higher. You should apply it generously and then remember to reapply every two hours or more often if you’ve been in the water or are sweating excessively.

Would you term UV a “sneaky” thing? List a couple facts about UV that have surprised any of your friends or family.

We should remember that sun safety is important all year around, not just in the summer. Snow, water and sand can all reflect UV rays upward and increase your chances of sunburn. A recent study showed that people remembered to put on their sunscreen more often just by storing it next to their toothpaste. Try it out!

Dig Deeper: Environment + Wellness

Want to explore how a changing climate has impacted your well-being? Check out our curated list of stories below.

The hotter it gets, the harder it is for your body to cool as you sleep.

The higher the ultraviolet (UV) index, the more you need to protect your skin and eyes to decrease the chance of skin cancer and cataracts.

With a wetter and warmer climate, Lyme disease and ehrlichiosis could become more common as the number of tick bites increase.