How to use the ultraviolet radiation index charts

The ultraviolet (UV) radiation monitoring network was upgraded in 2017 to produce a more robust and flexible network, with the capability to be expanded to more locations in the future.

We have also improved the way we present our ultraviolet radiation data. The UV index chart shows the ultraviolet radiation index throughout the day. The UV index chart shows two lines:

  • measured UV index
  • predicted UV index.

Key changes explained

Predicted UV

The dark blue dashed line shows what we predict the UV index will be throughout the day. This line is based on calculations using data that takes into account the time of the year and the height of the sun. The calculated UV index assumes that there will be no cloud cover, which is why it often differs from the measured UV index.

Real time UV

The light blue solid line shows the actual UV index measurement by our detectors. These detectors are measuring constantly and give you real time data every minute. We maintain a network of detectors in Australian capital cities and other high population areas.

Automatically refreshing charts

Our UV detectors are measuring data each minute. Select the 'Auto-refresh chart' checkbox if you would like to see a version of the chart which automatically updates to provide you with up-to-the-minute data. The automatically refreshing chart uses a cookie that is saved to your device. The cookie will be deleted from your device when you uncheck the 'Auto-refresh chart' checkbox.

Location settings

Our charts use the location settings on your device or browser to show information from your nearest location. When you visit the page, your browser or device will ask to use your location. If you do not allow the browser to use your location you will see Melbourne’s chart by default. If you continue to see Melbourne’s chart and want to see a chart closer to your location please enable the location settings of your browser or your device. Use the category and location drop down menus to manually change your location.

Select 'Make this my location' if you would like to save your location for future reference. The 'Make this my location' feature uses cookies that are saved to your device. Select 'Clear my location' under the 'My settings' menu if you would like to clear your default location. The cookie will be deleted from your device when you select 'Clear my location'.

Depending on your browser you may need to refresh your cache for the upgrade to take effect.

World Health Organization chart colours

We have added an option to view a version of the chart that uses colours recommended by the World Health Organization. Use the 'My settings' menus and select 'WHO colours' to view the chart with these colours. The WHO colour option uses a cookie that is saved to your device. The cookie will be deleted when you switch back to the 'Accessibility colours'.

Saving and downloading charts

The arrow symbol on the top right of the chart allows you to save an image of the UV chart in PNG, JPG, SVG or PDF format. The arrow symbol allows you to save a dataset of the graph in CSV, XLSX or JSON format and allows you to print a copy of the chart.


For improved accessibility we have included a table at the bottom of the chart showing what the predicted UV index will be and what the measured UV index was throughout the day on the hour.

Using the chart to protect yourself from the sun

If the UV index is less than 3 you can safely stay outdoors with minimal protection.

If the UV index is 3 or more we recommend you wear sun protective clothing, a hat, sunglasses, sunscreen and seek shade.

ARPANSA provides advice on how to best protect yourself from the sun.