Understanding the UV index and what it says about your risk

There has been a lot of talk recently about the UV index, and how it can be used to assess the risk from sun exposure. But how much do you really understand about what the UV index is and how it works? And can you really use it as a measure to indicate how much sun protection you need. We answer your frequently asked questions:

What is the UV index?

The UV index is a standardised measurement to show the intensity of UV (ultraviolet) radiation in a specific location and at a specific time. It was a joint development from the World Health Organisation (WHO) and the World Meteorological Organisation (WMO), to help people understand the level of UV radiation on any given day and take the precautions necessary to protect themselves.

How do I read the UV index?

The UV index is generally reported as a number between 0 and 11(+). As you might expect, 0 is the lowest level of UV – which only occurs at nighttime – and 11 is the highest. When the UV index is reported at 11, burn can occur within just ten minutes of exposure to the sun.

What’s the difference between the UV index and the weather forecast?

Many people think that the UV index is higher on a hot day and lower when it is cold. And this might be true, but the UV index is dependent on more than just temperature. Cloud cover can make a difference, as can altitude, because the atmosphere is thinner the higher up you go – which is why skiers are so prone to sunburn. In countries like New Zealand, which sits beneath a hole in the ozone layer, the UV index tends to be higher all year round than it is in Europe.

If the UV index is low, do I still need to protect my skin from the sun?

Absolutely. The UV index is great to give us an idea of the level of sun protection we need – if the reading is 11, for example, you may want to consider not going out into the sun at all unless it’s absolutely necessary – but it certainly shouldn’t be used as an indicator of whether we need to protect our skin at all. If you have very pale or sensitive skin, you could still burn even if the UV index is 1, depending on how long you are in the sun. And even those with darker skin tones can burn at level 2, if they stay outside for long enough.

What is the point of the UV index?

We are all at risk from excess UV exposure, but some people’s risk is greater than others. If you have previously had skin cancer, for example, protecting your skin from the sun becomes vitally important.

What is the bottom line?

The UV index is a fantastic tool to help us consider how much time we should be spending outdoors, or the level of sun protection we need. However, UV exposure can be harmful whatever the number, and we should all be wearing SPF 30+ – and topping it up at regular intervals – every day.

If you have any concerns about your risk from sun exposure or would like to discuss anything else with one of our team, please contact us.