Know the UV index

Have you heard of the UV index? Just like checking the weather to know if to dress for the heat, cold or rain every day, the UV index lets you know when you need to protect your skin from the sun’s ultraviolet (UV) radiation.  

The index ranges from 1 (low) to 11+ (extreme) and is updated throughout the day with real-time UV information from the Bureau of Meteorology.

The higher the UV index, the greater the potential for damage to your skin that can lead to skin cancer.

The UV index is an important tool because UV cannot be seen or felt. In fact, you can still get burnt and damage your skin on days that are cool or cloudy.

Our recommendation

Get in the habit of checking the UV index every day. You can receive personalised daily UV alerts on your phone by downloading Cancer Council’s free SunSmart app.

If the UV Index is 3 or above, remember to slip, slop, slap seek and slide.

How do UV rays cause skin cancer?

UV radiation from the sun can cause damage to the DNA in skin cells leading to skin cancer.

Melanocytes are a type of skin cell located in the upper layer of the skin. Melanocytes produce a brown black pigment called melanin which gives skin its colour. When melanocytes receive too much UV it can cause mutations to the cell’s DNA. If these mutations are not repaired by the body, they can lead to melanoma – the most deadly form of skin cancer.

95% of melanoma and 99% of non-melanoma skin cancers are caused by overexposure to UV by the sun. Protecting your skin from UV is the best way to prevent melanoma and other skin cancers.

How is the UV index calculated?

The UV index changes every day and depends on where you are and what season it is. Australia’s Bureau of Meteorology (BOM) captures ozone data by satellites and forecasts the UV index for the next day by calculating ozone concentrations in the atmosphere, the time of day, the date, and your location’s latitude and altitude.

Watch our video about UV index

How and when do you check the UV index?

Make it a habit to look at the UV index before you go outdoors, just like checking the weather.

You can check the UV index for where you live or where you are visiting. We recommend you do a daily check. Then you know how to protect your skin for the day.

For personalised daily UV alerts on your phone, download Cancer Council’s free SunSmart app. Or, use the SunSmart widget to the right to check the UV Index in your location.

When should you protect your skin from the sun?

The general rule is to protect your skin from the sun when the UV index is 3 or above. A measure of 3 means the UV level is moderate and can damage unprotected skin.​

UV levels in New South Wales:

  • are high from August until May. This means you might still need sun protection on cool or cloudy days in Autumn and Spring
  • usually peak between 10am and 2pm when it is not daylight savings
  • usually peak between 11am and 3pm during daylight savings
  • are often extreme in summer. That means the UV level is 11 or more.

In summary, the UV is 3 or above most months of the year in New South Wales. Remember to protect your skin and slip, slap, slop, seek and slide, especially in the middle of the day when the UV is highest.​

More information and resources