Frequently Asked Questions

  • What is the UV index?

    The UV index is a simplified measure of the erythemal UV. It is the erythemal UV measured in Wm-2 x 40. This will give a numerical value in the range 1 to 10 or more.

    The integer values can then be used to give a quick and simple idea of the erythemal UV at any time and place.

    The UV index is used for public information, for example in weather forecasts, and is usually provided for the middle of the day when the sun is at its strongest.

    If you know the UV index at home, and know how your skin reacts to this amount of UV, then you can assess what will happen in a different place with a different UV index.

    In the UK the UV index rarely gets above 7, even on a sunny day in the middle of summer, so holiday destinations where the UV index will reach 10 will cause you to burn much quicker than you would at home, e.g. Spain, USA, New Zealand, Canada and Austria.

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