Mountains have a very peculiar climate, are an essential factor in the climate system and are excellent areas for monitoring weather and climate. Nevertheless there is still a lack of long term observations at these areas, mainly due to their harsh conditions for instruments and humans. This work describes the results obtained in the design, installation and operation during more than a decade of a mountain meteorological network located in Sierra de Guadarrama (Iberian Central System, Spain). This work includes information about the measuring strategy, objectives and performance of the network with some technical and operational conlussions that might be useful for the mountain meteorology observation community. Discussions about the representativeness of the data are shown. These are important for future users of this data base. Also some basic statistics of the available data is shown as a framework for further and deeper analysis. Finally some recommendations are made about mountain meteorology observation which could be taken into account for future improvements of this network or for other mountain meteorological networks.