Understanding UV and UV Rating

What does UV mean?

Ultraviolet (UV) radiation is radiation that is emitted by the sun. It is divided into three sub-sections:


The earth’s atmosphere blocks all UVC radiation and all but a small amount of UVB, so the ultraviolet radiation at the earth’s surface is mostly UVA and UVB. UVB is the most harmful for humans.

What is the SunSmart UV Alert?

The SunSmart UV Alert is reported daily in newspaper weather forecasts across Australia. The alert is used to raise public awareness of the risk of exposure to UV radiation and to encourage people to adopt appropriate sun protection measures. For best protection from the sun, a combination of sun protection measures is recommended, including;

Seeking shade
Wearing protective clothing that cover the arms and legs as well as the body
Wearing a hat that shades the face and neck
Wearing wrap around sunglasses
Using SPF30+ broad spectrum sunscreen which is reapplied every two hours
Is the SunSmart UV Alert issued every day?
The SunSmart UV Alert is issued by the Bureau of Meteorology when the UV Index forecast for the day is 3 or above, which can apply to most days. When the UV Index reaches 3 or above, skin damage and particularly sunburn can occur and the risk of skin cancer increases, so sun protection is required.

The alert identifies the times during the day that the UV index will reach 3 or above, so people know when to adopt sun protection measures.

How is the UV forecast developed?

The UV Index forecast provides the information for the SunSmart UV Alert for cities and towns across Australia. The UV rating system used by the Bureau of Meteorology has been adapted from the World Health Organisation Global Solar UV Index.

Why are there different forecasts for different parts of Australia?
UV levels are largely determined by latitude, cloud cover, time of year and time of day. For this reason it is important for Australians to understand that the UV index can change each day, and is different for each month and each season.

Also, because the northern states of Australia are closer to the equator they have a higher UV Index then the southern states. It is important for Australians to understand that the UV Index can change each day due to cloud cover, and is different each month and each season.

Australians should get into the habit of checking the UV Index regularly to see when they need to adopt effective sun protection behaviours.

Where can I find more information about the UV Index?
For further information on the UV Index, please refer to these websites;

Bureau of Meteorology


World Health Organization


Australian Radiation Protection And Nuclear Safety Agency (ARPANSA)



SunSmart UV Alert Brochure
Click here to download “SunSmart UV Alert – Your Daily Guide to Sun Protection”