The short answer
Most of the sun's damage to skin comes from ultraviolet (UV) rays. You can lower that exposure with shade, clothing, a hat, sunglasses, and sunscreen, and by avoiding the strongest midday sun. Protecting children matters because sunburns early in life raise skin cancer risk later.
UV rays from the sun are the main preventable cause of skin cancer.
Shade, clothing, a wide-brimmed hat, and sunglasses are your first line of protection.
The sun is usually strongest between about 10 a.m. and 4 p.m.
Sunscreen adds protection but works best alongside shade and clothing, not instead of them.
Choose how you want to understand this
The full explanation.
The simple version
Most of the damage the sun does to your skin comes from ultraviolet (UV) rays. Over time, that damage can lead to skin cancer, which is the most common cancer in the United States.
The good news is that sun protection is simple and works. You do not need to avoid the outdoors. You just need a few easy habits that lower how much UV reaches your skin.
Think of sun protection as layers: shade, clothing, a hat, sunglasses, and sunscreen — used together.
Seek shade, especially midday
UV rays are strongest in the middle of the day, usually between about 10 a.m. and 4 p.m. Planning outdoor time for the early morning or later afternoon can cut your exposure a lot.
When you are outside during peak hours, look for shade under a tree, an umbrella, or a shelter. Shade is one of the easiest ways to reduce UV without giving up your day.
A quick self-check is the shadow rule: if your shadow is shorter than you are, the sun's rays are strong right now.
Shade is free, easy, and one of the most effective tools you have.
Cover up with clothing
Clothing is a reliable barrier between your skin and UV rays. When possible:
- Wear long sleeves and long pants or a long skirt.
- Choose tightly woven fabrics, which block more UV than loose weaves.
- Darker or brighter colors often block more UV than pale ones.
- Look for clothing with a UPF (Ultraviolet Protection Factor) label if you spend a lot of time outdoors.
A wide-brimmed hat that shades your face, ears, and the back of your neck adds protection where sunscreen is easy to miss.
Clothing you don't have to reapply is protection you can count on all day.
Protect your eyes
Your eyes and the thin skin around them are sensitive to UV too. Sunglasses that block both UVA and UVB rays help protect against eye damage over time.
Wraparound styles also block rays that come in from the sides. This protection matters for adults and children alike.
Use sunscreen the right way
Sunscreen adds protection to the skin you cannot cover. Experts generally suggest a broad-spectrum sunscreen with an SPF of 30 or higher.
- Apply it generously to all exposed skin about 15 minutes before going out.
- Reapply at least every 2 hours, and after swimming, sweating, or toweling off.
- Do not forget spots like ears, the back of the neck, the tops of your feet, and your lips (use an SPF lip balm).
One caution: sunscreen is a helper, not a shield that lets you stay in the sun as long as you like. Use it along with shade and clothing, not instead of them.
Sunscreen works best as one layer of protection among several.
Protecting children
Sun safety in childhood matters for a lifetime. Blistering sunburns early in life raise the risk of skin cancer, including melanoma, later on.
- Keep babies under 6 months out of direct sun when you can; use shade and clothing rather than relying on sunscreen for very young infants.
- Dress older children in hats, sunglasses, and cover-up clothing.
- Make reapplying sunscreen part of the routine at the pool or beach.
- Set the example — kids copy the sun habits they see.
Building sun-safe habits early protects your child's skin for decades.
Remember the everyday sun
It is easy to think about sun protection only at the beach. But UV reaches you during everyday activities too — walking the dog, driving, gardening, watching a game. UV also passes through clouds and reflects off water, snow, and sand.
Small daily habits, like keeping sunscreen by the door or a hat in the car, add up to real protection over the years.
Words to know
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Common questions
When is the sun strongest?
In most places, UV rays are strongest from about 10 a.m. to 4 p.m. A simple guide is the shadow rule: if your shadow is shorter than you are, the sun's rays are strong and you should seek extra protection.
Do I need sun protection on cloudy or cool days?
Yes. UV rays pass through clouds, so you can get sun damage even when it is overcast or cool. Snow, water, and sand also reflect UV and can increase your exposure.
Can people with darker skin skip sun protection?
No. People of every skin tone can develop skin cancer. Darker skin has more natural pigment, which offers some protection, but it does not prevent skin cancer or UV damage. Sun protection is worthwhile for everyone.
What kind of sunglasses should I look for?
Choose sunglasses labeled to block both UVA and UVB rays. Wraparound styles protect the sides of your eyes too. This helps protect your eyes and the delicate skin around them.
Is a base tan a safe way to prepare for summer?
No. There is no such thing as a safe tan from UV. A tan is a sign that your skin has already been damaged by UV rays. Building a base tan does not protect you and adds to your lifetime UV exposure.
How can I protect my kids at the beach or pool?
Use shade such as an umbrella, dress them in sun-protective clothing and a hat, and apply sunscreen to skin that is not covered. Reapply after swimming or toweling off. Keep babies under 6 months out of direct sun when possible.
Questions to ask your doctor
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Last updated: 2026-07-04Next planned review: 2027-07-04
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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