The UV Index is a simple and informative way of describing the danger of solar UV radiation intensity. Each point on the Index scale is equivalent to 25 milliWatts/square metre of UV radiation.
The higher the Index value, the greater the potential for damage to skin. Sun protection measures are needed when the UV Index is 3 or above.
The forecast UV Index for clear sky conditions is the value at the beginning of the first hour of the (3-hourly) time period.
The UV Index forecast is produced by the European Commission Copernicus Atmosphere Monitoring Service (CAMS) which is managed by the European Centre for Medium Range Weather Forecasts (ECMWF).