Key points
- Excessive UV exposure caused about 1.2 million new non-melanoma skin cancers and 325,000 melanomas in 2020, and 64,000 premature deaths from non-melanoma and 57,000 from melanoma that year (WHO, fact sheet 21 June 2022).
- Skin cancer is highly preventable. WHO's measures: limit midday sun, seek shade, wear protective clothing, a broad-brimmed hat and wraparound sunglasses, and use broad-spectrum sunscreen — shade and clothing first.
- Sun protection should be used when the UV Index reaches 3 or above. Children and adolescents are particularly vulnerable, and childhood sunburn raises later skin-cancer risk (WHO, 21 June 2022).
- The WHO protection measures are for everyone, whatever their skin tone. A new growth, a sore that does not heal, or a change in a mole is the awareness-level prompt to see a clinician.
Direct answer: Skin cancer is highly preventable. Excessive ultraviolet (UV) exposure caused about 1.2 million new non-melanoma skin cancers and 325,000 melanomas in 2020, and 64,000 premature deaths from non-melanoma skin cancer and 57,000 from melanoma that year (WHO, fact sheet published 21 June 2022). The protection that works is ordinary and well established: shade in the middle of the day, clothing, a hat and sunglasses, and sunscreen on uncovered skin — used when the UV Index reaches 3 or above. This guide extends the UV Index Lookup tool; it does not repeat the tool's index, it explains why the index matters for skin.
The numbers: skin cancer and UV
The WHO figures are for 2020, the latest year in the fact sheet published 21 June 2022: about 1.2 million new cases of non-melanoma skin cancer and 325,000 new melanomas of the skin caused by excessive UV exposure, with 64,000 premature deaths from non-melanoma skin cancer and 57,000 from melanoma. Small amounts of UV are beneficial — the body makes vitamin D from sunlight — but excessive exposure is carcinogenic to humans. That is the whole of the story in one sentence: the same light that the body needs in small amounts causes cancer in large amounts.
In the United States, skin cancer is the most common cancer (CDC, “Sun Safety Facts”, page dated 17 June 2026; US-only). Most skin cancers are caused by too much UV exposure. The CDC also reports that more than one-third of US adults and more than half of US high-school students get at least one sunburn each year (US-only), and that sunburn at any age increases skin-cancer risk.
Types of skin cancer
WHO names three chronic skin effects of excessive UV exposure alongside premature skin ageing: melanoma, squamous cell carcinoma, and basal cell carcinoma. Melanoma is the least common of the three and the most serious; the other two are grouped as non-melanoma skin cancers. This page names the types so readers recognise the words when they meet them in official guidance. It does not describe what any of them looks like on an individual, and it does not help a reader tell one from another — that is a clinician’s job, and the “seek care” framing at the end of this page is the only prompt it gives.
Who is most at risk
Children and adolescents are particularly vulnerable to UV, according to WHO, and childhood sunburn raises later skin-cancer risk. That is why the protection measures matter most, and earliest, for children — and why the UV Index threshold below is a family rule, not an adult one. In the continental United States, CDC notes that UV rays are strongest between 10 a.m. and 4 p.m. daylight saving time; the WHO framing is the same idea in global terms — limit time in the midday sun.
Sun protection for darker skin tones
WHO’s sun-protection measures are for everyone, whatever their skin tone, and the UV Index threshold of 3 applies to everyone. People with darker skin do get skin cancer, including melanoma, and sunburn can be harder to see on darker skin — which is a reason to follow the same measures, not a reason to skip them. Shade, clothing, a hat, sunglasses and sunscreen are not measures for fair skin only; they are the measures for all skin. This section exists because most sun-safety material is written and photographed as if it were only for fair skin, and the gap it leaves is real.
What protection looks like
WHO’s protective measures, from the fact sheet of 21 June 2022: limit time in the midday sun; seek shade; wear protective clothing; wear a broad-brimmed hat; wear wraparound sunglasses that block 99–100% of UV-A and UV-B; and use broad-spectrum sunscreen on uncovered skin — with shade and clothing first, and sunscreen not used as a way to extend time in the sun. Avoid artificial tanning devices. Sun protection measures should be used when the UV Index reaches 3 or above.
CDC’s sun-safety advice adds the practical detail: broad-spectrum sunscreen of SPF 15 or higher, reapplied every two hours and after swimming, sweating or towelling off; and sunscreen is not recommended for babies aged six months or younger — keep infants out of the midday sun instead. One honest discrepancy: some dermatology guidance, including the American Academy of Dermatology, recommends SPF 30 or higher, against CDC’s SPF 15 or higher. The figures differ by source, so this page states CDC’s figure as CDC’s and does not blend the two. And UV reaches the ground on cloudy and cool days, and reflects off water, sand and snow — so a cloudy day is not a day off.
| UV Index | Band | Protection message |
|---|---|---|
| 0–2 | Low | Wear sunglasses on bright days; if you burn easily, cover up and use broad-spectrum sunscreen. |
| 3–5 | Moderate | Seek shade during midday hours; wear a shirt, sunscreen and a hat. |
| 6–7 | High | Seek shade during midday hours; wear a shirt, sunscreen and a hat, and wear sunglasses. |
| 8–10 | Very High | Seek shade during midday hours; wear a shirt, sunscreen and a hat, and wear sunglasses; unprotected skin can burn quickly. |
| 11+ | Extreme | Take all precautions and avoid being outside during midday hours. |
The table above is the WHO Global Solar UV Index scale. For today’s index at a place, use the UV Index Lookup tool on this site — it shows the published index and the official WHO scale message, and nothing more.
When to seek care
This page does not help a reader judge their own skin. Its only prompt is CDC’s awareness-level wording: a new growth, a sore that does not heal, or a change in a mole is a reason to see a clinician. That framing is deliberately narrow. It is not a checklist, and it is not expanded here into signs or self-examination steps — those belong in a clinical conversation, not on an awareness page.
Frequently asked questions
How can I protect my skin from the sun?
Seek shade in the middle of the day, wear protective clothing, a broad-brimmed hat and wraparound sunglasses, and use broad-spectrum sunscreen on uncovered skin — shade and clothing first.
What SPF sunscreen should I use?
CDC advises broad-spectrum sunscreen of SPF 15 or higher. Some dermatology guidance recommends SPF 30 or higher — the figures differ by source, so this page states CDC's figure as CDC's.
Do I need sunscreen on a cloudy day?
Yes — UV reaches the ground on cloudy and cool days, and it reflects off water, sand and snow.