One of the main propagation effects on interference between a satellite system and an adjacent microwave terrestrial path is the differential rain attenuation. In this paper a method to predict rain differential attenuation statistics, used for single-site interfered Earth-space systems, is extended to include double-site diversity systems. The modified method is again based on a model of convective rain cells as well as on the lognormal assumption for the point rainfall rate distribution at the location under consideration. Numerical results are presented concerning a realistic interfered satellite link using double-site diversity and located in Japan. Because of a lack of available experimental data, our attention has mainly been concentrated on the examination of the optimum coordination between the adjacent systems. Some very useful conclusions are deduced.