Planetary meteorologists seek to understand the origin and evolution of the family of planets that orbit the Sun to investigate the stability of their atmospheres and to compare the surface environment and climate with the Earth The radiative dynamical and chemical processes in Earth s atmosphere all have analogues on the other planets by studying all of them we learn more than by studying the Earth as an isolated example Space missions to the planets are now sufficiently numerous and sophisticated and computer models sufficiently versatile to make such studies meaningful This article reviews the current state of knowledge Copyright (C) 2010 Royal Meteorological Society