The UV index or ultraviolet index is the standard measurement used around the world to measure the strength of ultraviolet radiation at a particular time and place. The UV index scale is used internationally and was developed by Canadian scientists in 1992 and then adopted by the United Nation’s World Health Organization and Meteorological Organization two years later.
The UV index is mostly used in daily forecasts which are aimed at the general public. The UV index has even been developed to become increasingly available and forecast alongside the weather every hour.
What is the purpose of the UV index?
The UV index has been created to help people protect their skin from UV radiation. If someone receives too much UV radiation, this can cause sunburn, DNA damage, skin cancer and excessive skin ageing.
The UV index scale is implemented into weather forecasts to tell you whether you should protect yourself or not. If the UV index is extremely high, you will need extra protection and if it is very low, you will only need minimal protection.
How does the scale of the UV index work?
The UV index starts at 0 and it is an open-ended linear scale that is directly proportional to the intensity of UV radiation and the sunburn it causes on exposed human skin.
0-2 UV index, low – A UV reading of 0-2 means that there is a low danger of getting sunburnt by the suns UV rays for the average person. If you burn easily, then try to cover up.
Remember that if you are spending time around bright surfaces such as water, sand and snow, you will have to take into consideration the increased UV exposure. The time to burn can vary from person to person but a UV index of 0-2 can take around 60 minutes to burn exposed unprotected skin.
3-5 UV index, moderate – A UV index of 3-5 is strong and requires sun cream and it is best to seek shade during the midday when the sun is strongest. The time to burn can vary from person to person but a UV index of 3-5 can take around 30-45 minutes to burn exposed unprotected skin.
6-7 UV index, high – When the UV index is between 6 and 7, it means that the risk of unprotected skin getting burnt is high. Seek shade during midday and use sunscreen and clothing to protect against eye and skin damage. The time to burn can vary from person to person but a UV index of 6-7 can take around 15-25 minutes to burn exposed unprotected skin.
8-10 UV index, very high – A UV index between 8 and 10 means that the skin is at a very high risk of burning when exposed to the sun. Avoid going out in the sun between 10 am and 4 pm and apply sunscreen every 1.5 hours or after sweating/swimming. The time to burn can vary from person to person but a UV index of 8-10 can take around 15 minutes to burn exposed unprotected skin.
11+ UV index, extreme – A UV index that is 11 or higher means extreme risk of harm on skin that is not protected. Take all precautions when the UV index is above 10 because the skin can burn in just minutes if it is unprotected.
Try to avoid going out into the sun between 10 am and 4 pm as this is when the sun is the strongest. If you have to go outside try to remain in the shade, wear sun-protective clothes, a large hat, sunglasses and sunscreen. Apply sunscreen every 1.5 hours and after swimming or sweating. The time to burn can vary from person to person but a UV index of 11+ can take less than 10 minutes to burn exposed unprotected skin.