The role of scale in the rainfall characterizations resulting from different rainfall models is the main issue under study. Three different types of models are analyzed : temporal rainfall models at a point, areal storm rainfall models, and space-time rainfall representations. The perspective is taken that precipitation models need mainly to incorporate those features of the process which lead to an adequate representation under some amount of local averaging either in time or in space or in space and time. Thus the characteristics of the averaged rainfall process resulting from the different models are analyzed with a special emphasis on the role of the scale of fluctuation of the process in these characteristics.