What is the UV index?

The UV index measures the strength of the sun's ultraviolet radiation at the Earth's surface on a scale from 0 (no risk) to 11+ (extreme). In Australia, UV regularly reaches 11+ in summer — among the highest in the world.

When is UV highest in Australia?

UV is strongest between 10am and 3pm AEST/AEDT, typically peaking around solar noon. Levels are highest in summer (December–February) and across northern Australia year-round.

Can you get sunburnt when the UV index is below 3?

Skin damage from UV is unlikely when the index is below 3, so sun protection generally isn't required. However, people with very fair skin or those on photosensitising medication should still take care.

What UV level requires sun protection?

Cancer Council Australia and ARPANSA recommend sun protection (SPF 50+ sunscreen, hat, sunglasses, protective clothing, shade) whenever the UV index reaches 3 or higher.

How accurate is the UV index forecast?

Forecasts use validated solar radiation models (Open-Meteo, ARPANSA, ECMWF) and are accurate to within ±1 UV unit under clear skies. Heavy cloud, smoke or haze can lower actual UV by 20–80%.

Does cloud cover block UV radiation?

No — up to 80% of UV passes through light cloud cover. You can still get sunburnt on overcast days, especially when the forecast UV is 6 or higher.

Cairns UV Index — Live Readings & Forecast

Name: UV index observations and forecast — Cairns
Creator: Open-Meteo
License: https://open-meteo.com/en/license

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Live UV index — Cairns

Current UV reading and outlook for the next 12 hours. Data refreshes hourly from Open-Meteo.

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Compare Cairns's UV reading with other centres in Queensland.

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7-day UV forecast — Cairns

Daily peak UV index for the next week. Sun protection is required whenever UV reaches 3 or above.

Cairns sits in the tropics at 17°S and records extreme UV (11+) for virtually every month of the year. Even during the wet season, when cloud cover is at its heaviest, the UV index frequently exceeds 9. The Great Barrier Reef, Daintree rainforest and Trinity Beach draw outdoor visitors year-round, and reef-snorkelling exposure is intensified by water reflection — up to 25% of UV reflects from the sea surface, with additional scatter from white sand. Cancer Council Queensland and ARPANSA both highlight Cairns as one of Australia's highest-risk UV environments. Sun protection is recommended continuously during outdoor activity, with reef-safe SPF 50+ sunscreen, UPF-rated clothing, broad-brimmed hats and shade essential whenever the UV index reads 3 or higher — effectively every daylight hour in Far North Queensland.

Peak UV season in Cairns: year-round; extreme August to April.

UV Index Scale & Sun Protection

Low (0–2)
No protection required
Moderate (3–5)
Sunscreen, hat, sunglasses
High (6–7)
Protection essential, seek shade midday
Very High (8–10)
Extra protection, avoid sun 10am–4pm
Extreme (11+)
Stay indoors when possible

Scale follows the WHO/ARPANSA Global Solar UV Index. Source: ARPANSA & Cancer Council Australia.

Sun protection in Cairns

Cancer Council and ARPANSA recommend the SunSmart five whenever the UV index reaches 3: slip on protective clothing, slop on SPF 50+ sunscreen, slap on a broad-brimmed hat, seek shade and slide on sunglasses. UV is invisible and unrelated to temperature — cool, overcast days in Cairns can still deliver a sunburn dose because up to 80% of UV penetrates light cloud.

National UV index hub →7-day Australian UV forecast →UV index Queensland →Cairns weather hub →

UV Index Cairns — FAQs

UV data: Open-Meteo. Reference guidance: ARPANSA, Cancer Council Australia, Bureau of Meteorology.