The UV index: a simple guide for Australians

You cannot see UV and you cannot feel it. That is why the UV index exists. It is a simple number that tells you how strong the sun's UV is where you are, and when you need to cover up. Here is how to read it and use it to plan your day.

What the UV index is

The UV index measures the strength of the sun's ultraviolet radiation. The higher the number, the faster UV can damage your skin and eyes. Cancer Council groups the numbers like this:

The number to remember is 3

Cancer Council's advice is simple. Whenever the UV index is 3 or above, use all five SunSmart steps:

• Slip on clothing that covers your skin, such as long sleeves.
• Slop on SPF 50 or 50+ broad-spectrum, water-resistant sunscreen, and reapply every two hours.
• Slap on a broad-brimmed hat to shade your face, neck and ears.
• Seek shade.
• Slide on sunglasses that meet the Australian standard.

Cancer Council also says that when the UV is 3 or above, just 15 minutes of unprotected sun is enough to start damaging your skin. That is less time than a single hole of golf.

UV is not the same as heat

This catches a lot of people out. The warmth you feel is a different kind of energy from UV. Cancer Council explains that temperature does not change UV levels. The UV can be just as high on a cool day as on a hot one, especially under clear skies.

Cloud is not a reliable guide either. Thick cloud filters UV well, but UV can get through thin cloud. So a mild, breezy or overcast morning on the green can still call for sun protection. Check the number, not the thermometer.

Why Australians need to pay attention

Cancer Council notes that Australia has some of the highest levels of UV radiation in the world. UV is higher in summer, but it is present every day of the year.

Levels also change with where you are, the time of day, the time of year, altitude and cloud. Two towns can have quite different UV on the same day, so always check your own location.

When is the UV highest?

Cancer Council says peak UV hours are usually between 10am and 4pm. The exact times change through the year and across the country.

The Bureau of Meteorology issues "sun protection times" for your location whenever the UV is forecast to reach 3 or above. These are the hours when you need to take care. They are the easiest way to plan a tee time, a garden job or a walk.

Where to check the UV

• The SunSmart Global UV app. Free from Cancer Council. It shows live UV, daily sun protection times and a seven-day forecast, and it can send you an alert when the UV reaches 3.
• The Bureau of Meteorology. Sun protection times are on the BOM website and app, next to your local forecast.
• ARPANSA. ARPANSA runs UV detectors in cities around Australia and publishes live UV readings on its website.
• The newspaper weather page. Most daily papers print the UV index.

Plan your day around it

A few simple habits make the UV index part of your routine:

• Check it with the weather. When you look at the forecast in the morning, look at the sun protection times too.
• Book around the peak. If you can, choose an early tee time or a later bowls session, and do the heavy garden jobs outside the peak hours. Check the times for your town first.
• Keep your kit by the door. Hat, sleeves, sunscreen and sunglasses in one spot means you do not have to think about it.
• Do not forget the car. Car glass blocks most UVB, but side windows can let through more UVA than the windscreen, says Cancer Council. In Australia your right arm is by the window. In the US it is your left. See sun through a car window.

Gardeners will find more in the best time to garden by UV.

Where arm sleeves fit in

Arm sleeves are part of the "slip" step. A UPF 50+ sleeve blocks 98% or more of UV from the arm it covers, and it does not need reapplying. They do not cover your face, neck or hands, so the other steps still matter.

IceRays sleeves were tested by ARPANSA in 2015 (black sample) and rated UPF 50+. See what the test covered on our test report page (PDF, opens in a new tab). One size fits all adults. A 4-pack is AUD 120, which is $30 a pair and saves $31.80 compared with four single pairs. In the US it is USD 100.

Read more in what UPF 50+ means, arm sleeves vs sunscreen and the complete guide to UV arm sleeves.

Related guides

• Hiking sun sleeves: prepare for exposed parts of the trail
• Lawn bowls SunSmart guide: sun safety for clubs and players
• UPF vs SPF: what the rating on sun protective clothing actually means