UV Index

Ultraviolet (UV) radiation is the invisible killer that you can't see or feel. UV radiation can be high even on cool and overcast days. This means you can't rely on clear skies or high temperatures to determine when you need to protect yourself from the sun.

Exposure to UV radiation from the sun and other sources, such as solariums, is the major cause of skin cancer. Australia has some of the highest levels of UV radiation in the world – in fact, UV radiation is strong enough to cause sunburn in as little as 11 minutes on a fine summer day.

UV radiation from the sun is also one of the best natural sources for vitamin D so a balance is important.

What is UV radiation?

UV is a form of energy produced by the sun. The sun produces different types of energy:

• Visible light – which we can see as sunlight.
• Infrared radiation – which we feel as heat.
• UV radiation – which we cannot see or feel.

UV radiation is often confused with infrared radiation. The temperature, however, does not affect UV radiation levels. UV radiation can be just as high on a cool or even cold day as it is on a hot one, especially if skies are clear. Thick cloud provides a good filter, but UV radiation can penetrate thin cloud cover. And while UV radiation is higher in summer than in winter, it is still present every day of the year.

There are three types of UV radiation, categorised by wavelength: UVA, UVB and UVC.

• UVA can cause sunburn, DNA (cell) damage in the skin and skin cancer.
• UVB causes skin damage and skin cancer. Ozone stops most UVB from reaching the earth’s surface, about 15% is transmitted.
• UVC is the most dangerous type of UV. Ozone in the atmosphere absorbs all UVC and it does not reach the earth’s surface.

UV levels are affected by a number of factors including geographic location, altitude, time of day, time of year and cloud cover. This means that UV levels are higher in some parts of Australia than others even on the same day.

What is the UV Index?

The UV Index is a tool you can use to protect yourself from UV radiation. It tells you the times during the day that you need to be SunSmart.

The UV Index divides UV radiation levels into:

• low (1-2)
• moderate (3-5)
• high (6-7)
• very high (8-10)
• extreme (11 and above).

The Australian Radiation Protection And Nuclear Safety Agency (ARPANSA) measures the UV index in a location at each of Australia’s capital cities and makes this real-time data available on a daily basis. Check the ARPANSA website to see what the UV levels have been in your capital city today.

Sun protection times are issued by the Bureau of Meteorology when the UV Index is forecast to reach 3 or above. At that level, it can damage your skin and lead to skin cancer. Sunscreen should be incorporated into your daily routine on these days.

How do I get the UV Index?

The Index is reported in the weather page of all Australian daily newspapers, on the Bureau of Meteorology website, and on some radio and mobile weather forecasts. You can also find UV Alerts on the ARPANSA website.

SunSmart App

For smartphone users, our free SunSmart app is a great way to check the UV Index when you are out and about. iPhone users can download it at the iTunes App Store and Android users at the Google Play store.

So whether you are at work, home or on the move, you can easily and quickly check the times of the day when sun protection is needed.

_{If you’ve downloaded the previous version of the SunSmart app, delete it from your phone and download our new SunSmart Global UV app for your daily UV and sun protection information. The current SunSmart app will be removed from the app store in July 2023.}

When should I use the UV Index?

Look or listen for the UV Index when you are:

• planning or participating in an outdoor activity or event
• undertaking recreational activities such as running, swimming, cycling or team sports
• watching a spectator sport, such as tennis or cricket
• working outdoors, or have responsibility for outdoor workers, or
• responsible for young children and their outdoor activities.

If sun protection times have been issued, you need to protect yourself during the times indicated.