In this article, the predictability of the 20th century sea-surface temperature (SST) forced East African short rains variability is analyzed using observational data and ensembles of long atmospheric general circulation model (AGCM) simulations.To our knowledge, such an analysis for the whole 20th century using a series of AGCM ensemble simulations is carried out here for the first time.The physical mechanisms that govern the influence of SST on East African short rains in the model are also investigated.It is found that there is substantial skill in reproducing the East African short rains variability, given that the SSTs are known.