The global distribution of precipitation is an outstanding example of a pattern whose form cannot be deduced very satisfactorily from conventional observational data. Many investigations of the global hydrological cycle across real periods of time are based on broadly generalized assumptions concerning rainfall patterns, especially over the world's oceans. This paper explores the feasibility of employing observational data from meteorological satellites to yield more acceptable maps of rainfall across periods of 1 mo and upward than is possible using conventional surface measurements, whose distributions are less uniform, and whose derivations are more heterogeneous, than the satellite data coverage. The central problem is related to the fact that satellites cannot measure rainfall directly, and the solution of this problem necessitates the construction of a rainfall coefficient equation to be evaluated from nephanalysis indications of cloud cover. Evaluated coefficients for the months of March, ... Abstract The global distribution of precipitation is an outstanding example of a pattern whose form cannot be deduced very satisfactorily from conventional observational data. Many investigations of the global hydrological cycle across real periods of time are based on broadly generalized assumptions concerning rainfall patterns, especially over the world's oceans. This paper explores the feasibility of employing observational data from meteorological satellites to yield more acceptable maps of rainfall across periods of 1 mo and upward than is possible using conventional surface measurements, whose distributions are less uniform, and whose derivations are more heterogeneous, than the satellite data coverage. The central problem is related to the fact that satellites cannot measure rainfall directly, and the solution of this problem necessitates the construction of a rainfall coefficient equation to be evaluated from nephanalysis indications of cloud cover. Evaluated coefficients for the months of March, ...