Although many of the requirements for the measurement of precipitation amount may be met by the stations in the climate network, it is important for some applications to be able to resolve detail on smaller space scales. Point to point variability, and therefore the interpolation error between two neighbouring stations, is larger for rainfall than for most other climate elements. In terms of station numbers, the rainfall network is largest having some 5000 stations currently open across the UK. Radar rainfall sites are not included in this network. The current rainfall network is made up of 3 sub-networks:.