A cloud plume is generated by the interaction of low-level easterly flow and diurnal surface heating on the island of Nauru in the tropical Pacific. Diurnal and seasonal cycles of cloud plume length, frequency, and heading were obtained by inspection of a year of hourly daytime GMS images. The cloud plume extends downwind and typically grows during the day to a mean length of 125 km by late afternoon with a maximum observed length of 425 km. The longest average plumes occur during March and April. The afternoon plume frequency was 63% compared to 50% for all observations. Further evaluation of the plume effects is needed to fully assess their impact on the development of long-term statistics of cloud and radiation parameters derived from surface instruments on the island's leeward side. ¿ 2001 American Geophysical Union