Observations of wind are required from the synoptic network to meet the real time needs of forecasting and NWP and have usually always been based on 10-minute averages. The climatological requirement for wind measurement is more varied and observations using a wider range of averaging periods have been made. Although some wind-only sites exist, observations of wind are usually collocated with observations of other meteorological elements. The wind network is made up of 3 sub-networks.