Sunlight is essential for health, but it also carries its risks.
The strength of UV varies depending on where you are in the world, the time of year and on a number of different weather factors such as the amount of cloud cover. Small amounts of UV exposure can be beneficial as it is essential in the production of vitamin D, however over exposure of UV can lead to serious health issues.
Our UV index forecast is produced all year round for 417 world cities, mainly across Europe. In the UK the forecast is predominantly throughout the summer months, with late June seen as the peak, however this is dependent on weather conditions.
Our UV index forecast identifies the strength of the ultraviolet (UV) radiation from the sun at a particular place on a particular day, allowing you to take the necessary precautions to help reduce the impact of UV on your health.
Our forecast is designed to warn you of an increased risk to your health from UV radiation and encourage you to take actions that reduce these risks but still allow you to enjoy the benefits of the sun.
The 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:
Our 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 and skin damage.