Significant relationships on time scales longer than 5 years are demonstrated between northern Pacific sea surface temperatures, North Atlantic tropical cyclone numbers, and northeastern Australian rainfall. In agreement with previous work, the global nature of these correlations suggests that they are indications of an intrinsic interdecadal mode of oscillation in the global ocean-atmosphere system. The persistence in time of the sea surface temperature variations may enable forecasts to be made of North Atlantic tropical cyclone numbers several years in advance. A similar capability for the prediction of north-eastern Australian rainfall is also shown. Thus these relationships may be useful as an aid in long-term planning decisions. ¿ 1997 American Geophysical Union