Universality of the rainfall phenomenon

We show that the universal properties of the rainfall phenomenon are the scaling properties of the probability density function of inter-drop intervals during quiescent periods, time intervals of sparse precipitation, and the universal shape of the probability density function of drop diameters during non-quiescent periods, time intervals of active precipitation. Our results indicate that the continuous flux-like vision of rainfall based on quantities such as the rain duration, rain intensity and drought duration is ineffective in detecting the universality of the phenomenon. A comprehensive understanding of rainfall behavior must rest on the acknowledgment of its discrete drop-like nature.