This European Standard specifies procedures for calculating and presenting the monthly means of those parameters of climatic data needed to assess some aspects of the thermal and moisture performance of buildings. Numerical values should be obtained from the meteorological service in the relevant country. This European Standard covers the following single climate variables: _ air temperature; _ atmospheric humidity; _ wind speed; _ precipitation; _ solar radiation; _ longwave radiation. Meteorological instrumentation and methods of observation are not covered; these are specified by the World Meteorological Organisation (WMO).