Understanding the UV Index

The UV forecast is expressed as a ‘Solar UV Index’, a system developed by the World Health Organization.

The Met Office UV forecasts include the effects of:

• the position of the sun in the sky

• forecast cloud cover

• ozone amounts in the stratosphere

Forecasters gather all this information and input it in to the easy to understand index from 1 to 11+,
which determines your level of exposure to ultraviolet radiation.

The UV index does not exceed 8 in the UK (8 is rare; 7 may occur on exceptional days, mostly in the two
weeks towards the end of June). Indices of 9 and 10 are common in the Mediterranean area.

The aim of the index is to warn people of increased risk and encourage them change their behaviour in
order to protect themselves against the risks of skin cancer, skin damage and premature ageing.

Skcin recommend that people start to take sensible UV protection precautions as soon as the UV is at a moderate level/is displaying in a yellow triangle.