It is well known how mountains play a crucial role in the climate system and have very particular climate features compared to other regions. Sierra de Guadarrama is a part of the Iberian Peninsula Central System (Spain), a mountain range located in the center of an extensive plateau, dominated by a continental Mediterranean climate but under a strong Atlantic influence. This range provides fresh water to the different settlements in its vicinity, providing enough water resources to several millions of inhabitants, crop fields, industries and the city of Madrid, the capital of Spain. Nevertheless, there is no work studying the role of the synoptic scale in relation to the precipitation in this mountain range. To tackle this problem, this work calculates water vapour flux patterns (WVFPs) using total column water vapour flux as a predictor field due to the close relation between this parameter and the precipitation in mountainous areas. A clustering analysis on the first three principal components of the predictor field was performed and seven differentiated WVFPs were found using a cost function considering local precipitation data for optimum number of cluster determination. Then, an analysis is made for each component in terms of synoptic relation with other fields and well-known broader teleconnection patterns. Finally, an analysis in terms of their contribution to total precipitation, mean rain intensity and probability of precipitation is made. This work is expected to bring new light on the knowledge of precipitation climatology over this crucial and still not very well-known area, and it is a solid step for future precipitation modelling tools validation that combined with reliable measurements will allow to produce realistic precipitation assessments and forecasts in order to improve the hydrological management of this complex area.