You can't feel UV radiation. You can't see it. But every day, even on cloudy days, it's reaching your skin and causing harm that builds up over a lifetime.
UV stands for ultraviolet, a type of energy that comes from the sun (and from some artificial sources like solariums). It sits just beyond the visible light spectrum, which is why you can't see it.
There are three types of UV radiation: UVA, UVB, and UVC. UVC is absorbed by the Earth's atmosphere and doesn't reach us. But UVA and UVB both reach our skin every single day, and they each cause different kinds of damage.
In Australia, UV radiation levels are among the highest in the world. Our position close to the equator, combined with a thinner ozone layer over parts of the southern hemisphere, means Australians are exposed to UV radiation that is significantly more intense than in Europe or North America.
Think of them as two different threats, one that strikes fast, and one that works slowly in the background.
The "Ageing" ray
UVA rays make up about 95% of the UV radiation that reaches Earth. They have a longer wavelength, which means they penetrate deeper into your skin, all the way down to the dermis, where collagen and elastin live.
UVA rays are present all year round, from sunrise to sunset, and they pass straight through glass, meaning you're exposed even when you're sitting inside near a window or driving in your car.
What UVA does to your skin:
The damage from UVA is cumulative and largely invisible until years later, which is what makes it so dangerous.
The "Burning" ray
UVB rays have a shorter wavelength and are more energetic. They don't penetrate as deeply as UVA, but they hit the outer layers of skin with more intensity, and they're the primary cause of sunburn.
UVB intensity varies throughout the day, it's strongest between 10am and 3pm, and by season. But in Australia, UVB levels can be dangerously high even in winter, especially in northern states.
What UVB does to your skin:
Every sunburn, even a mild one, increases your lifetime risk of skin cancer. There is no such thing as a "safe" tan.
UVA and UVB work differently, but they both contribute to the same outcome: DNA damage that accumulates over years and decades, eventually leading to skin cancer.
The cruel irony is that much of this damage happens without any warning signs. You don't feel UVA rays. A tan, which many people still associate with health, is actually your skin's distress signal: a sign that DNA damage has occurred and your body is trying to protect itself.
DNA damage
Both UVA and UVB directly damage the DNA inside your skin cells, the first step toward cancer.
No warning signs
Most UV damage is invisible and painless. By the time you see signs, years of harm have already been done.
Eyes at risk too
UV radiation damages your eyes as well as your skin, contributing to cataracts and macular degeneration.
The UV Index in Australia regularly reaches 11 or above, classified as "Extreme", even in winter in northern regions. In summer, levels of 14 or higher are common in many parts of the country.
For context, a UV Index of 3 is considered "moderate" in most European countries and is when sun protection is recommended. Australia regularly operates at 3–5 times that level. Yet we have no national program to ensure every Australian has access to sunscreen.
The UV Index (UVI) is a simple number that tells you how strong the sun's UV radiation is on any given day. The higher the number, the faster your skin can be damaged, and the more protection you need. Australia uses the same international scale as the WHO.
Low
UV Index 1–2
Minimal risk for the average person. You can safely spend time outside without protection, though fair-skinned people may still want to take care.
Rare in Australia
Possible in winter,
southern states
Moderate
UV Index 3–5
Unprotected skin can burn. Sun protection is recommended, especially between 10am–3pm. Seek shade during peak hours.
Common in Europe
Australia's "low" days
in winter
High
UV Index 6–7
Skin can burn in as little as 15–25 minutes. Full sun protection is essential. Reduce time outdoors during peak hours.
Typical Australian
winter day in
northern states
Very High
UV Index 8–10
Skin can burn in under 15 minutes. Take every precaution, full coverage clothing, SPF 50+, hat, sunglasses, and shade. Avoid the sun between 10am–3pm where possible.
Common in Australia
Spring & autumn
across most states
Extreme
UV Index 11+
Unprotected skin can burn in as little as 10 minutes or less. Avoid being outdoors during peak hours if at all possible. If you must go out, cover every exposed area of skin.
Australia's reality
Summer across most
of the country
Most of Europe and the UK rarely exceeds a UV Index of 6–7, even in peak summer. In Australia, a UV Index of 3 is considered a low day. Our summer UV regularly hits 11–14+, classified as Extreme, across most of the country.
Even in winter, northern Australia (Queensland, Northern Territory, Western Australia) regularly records UV Index levels of 8–10, classified as Very High. In Australia, there is no such thing as a "safe" season for UV exposure.
14+
Typical summer UV Index in Darwin and northern Queensland
11–13
Summer UV Index across Sydney, Melbourne, Perth, Adelaide
8–10
Winter UV Index in Queensland and the Northern Territory
Check today's UV Index for your city. The data updates hourly so you always know what protection you need before heading outside.
Remember: UV radiation is invisible. A cool, cloudy day can still have a dangerously high UV Index, especially in Australia. Always check before you go out.
No special precautions needed for most people.
Data from Open-Meteo. Updated hourly. For official BOM UV forecasts, visit ARPANSA.
Download the UV Index Guide
A printable one-page PDF of the full UV Index scale with protection guidelines, suitable for schools, workplaces, and community noticeboards.
Most people apply far too little sunscreen, and skip reapplication entirely. This dramatically reduces real-world protection, even with SPF 50+. Here's how to do it right.
Sunscreen needs time to bind to your skin and form a protective layer. Applying it right before you walk out the door means you're unprotected for the first 20 minutes of sun exposure.
Tip: Make it part of your morning routine, apply after moisturiser, before you get dressed.
The SPF rating on a bottle is tested at 2mg per cm² of skin. In practice, most people apply only 25–50% of the required amount, meaning your actual protection could be SPF 10–15, not SPF 50+.
Tip: For the average adult: about 1 teaspoon for your face and neck, 1 teaspoon per arm, 2 teaspoons per leg, and 2 teaspoons for your torso (front and back). That's roughly 35ml (7 teaspoons) for full-body coverage.
Ears, the back of the neck, the tops of your feet, the back of your hands, your scalp (use a hat or spray sunscreen), and the back of your knees are commonly missed.
Tip: Ask someone to help with your back, or use a spray sunscreen for hard-to-reach areas.
Sunscreen breaks down with sun exposure, sweat, and water. After 2 hours, your protection is significantly reduced, regardless of the SPF rating. Reapply immediately after swimming, towelling off, or heavy sweating.
Tip: Set a phone reminder if you're spending a long day outside. A single application in the morning is not enough for a full day outdoors.
Expired sunscreen may not provide its stated SPF protection. The active ingredients degrade over time, especially if the product has been stored in a hot environment (like a car or beach bag).
Tip: Write the date you opened the bottle on the cap. Most sunscreens are good for 2–3 years unopened, but should be used within 12 months of opening.
The Cancer Council recommends a "5 S" approach to sun protection: Slip on sun-protective clothing, Slop on SPF 50+ sunscreen, Slap on a broad-brimmed hat, Seek shade, and Slide on UV-protective sunglasses.
Sunscreen is one layer of protection, not a licence to stay in the sun all day. Combine it with shade, clothing, and hats for the best protection.
The good news is that sunscreen, when it works as labelled, blocks both UVA and UVB radiation. Broad-spectrum SPF 50+ sunscreen, applied correctly and reapplied regularly, is one of the most effective tools we have.
The problem? Sunscreen costs money. For many Australians, particularly young people, families, outdoor workers, and those on lower incomes, the cost of daily sunscreen use is a real barrier. And as recent testing has revealed, not all sunscreens even deliver the protection they promise.
That's why UVI3 is calling for a National Sunscreen Program, to make proven, effective sun protection freely available to all Australians, in the same way we fund vaccines and road safety campaigns.
Read Next
Understanding UV radiation is only half the picture. Learn what SPF really means, the difference between SPF 30+ and SPF 50+, and the shocking 2025 CHOICE investigation that found 16 out of 20 Australian sunscreens failed to deliver the protection on their label.
Understanding SPFUV radiation is invisible, cumulative, and preventable. Help us make protection the norm, not the exception.