In the literature on time series analysis it has been established in recent years that the hydrological/meteorological time series are well described by nonlinear models, in particular by the SETAR (Self- exciting threshold au- toregressive) models. In this paper, a nonlinear SETAR model is fitted to the precipitation variable that is observed in a certain Colombian hydrologi- cal/meteorological station. In the fitting process, two alternative methodolo- gies, which have been proposed in the literature about nonlinear time series models, are combined.