Simple, regression-derived formulas have been generated to estimate differential rain attenuation statistics on converging microwave paths. The proposed expressions are based on a regression fitting analysis implemented on an existing analytical model. The resulting simple model is tested with experimental data taken from Brazil with very good agreement. The impact of differential rain attenuation on the interference performance of a local multipoint distribution system (LMDS) is also studied.Index Terms-Differential rain attenuation, interference local multipoint distribution system (LMDS)/local multipoint communication systems (LMCS), terrestrial communications.