How does the UV Index work?
We are frequently reminded of the importance of sun safety and protecting ourselves from ultraviolet (UV) radiation to avoid skin cell damage, which leads to premature signs of ageing and skin cancer. This hyper-vigilance is for good reason, with around 800,000 skin cancers diagnosed in Australia every year.
UV radiation is emitted by the sun and is responsible for the vast majority of skin cancers. It is not related to light or temperature, so you can't see or feel it. In fact, it is a common misconception that you can 'feel yourself getting sunburnt' or that you can't get sunburnt on a cool day.
UV radiation can be reflected by light and shiny surfaces such as sand, snow, concrete and water. Cloud coverage does not decrease UV radiation levels at ground level.
There are several main types of UV radiation. UVA rays cause skin ageing such as wrinkles. UVB rays cause tanning and sunburn, thereby increasing your skin cancer risk. UVC rays do not reach Earth's surface but can be produced artificially (for example, by welding equipment).
Australians are subjected to high levels of UV radiation throughout the year, even in winter and especially in northern parts of the country. UV radiation is measured according to the UV Index.
The UV Index
The UV Index provides a consistent and international measure of the sun's ultraviolet strength. It measures radiation on a scale of 1 to 11 and beyond. The higher the number, the stronger the radiation levels and the faster your skin will burn.
You are at risk of skin damage when the UV Index is at 3 or above. In Australia, this can be year-round.
- 0-2 = Low. No protection required, except for very fair skin.
- 3-5 = Moderate. Protect yourself in 5 ways.
- 6-7 = High. Protect yourself in 5 ways.
- 8-10 = Very High. Protect yourself in 5 ways and reschedule your outdoor activities until UV levels decrease.
- 11+ = Extreme. Protect yourself in 5 ways and avoid going outside.