Results are described from a large sample of coupled ocean–atmosphere retrospective forecasts during 1980–2006. The prediction system is based on the National Center for Atmospheric Research (NCAR) Community Climate System Model version 3 (CCSM3.0) and a state-of-the-art ocean data assimilation system made available by the National Ocean and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory (GFDL). The retrospective forecasts are initialized each January and July of each year, and ensembles of six forecasts are run for each initial month, yielding a total of 324 1-yr predictions. In generating the ensemble members, perturbations are added to the atmospheric initial state only. The skill of the prediction system is analyzed from both a deterministic and a probabilistic perspective and is compared to the operation NOAA Climate Forecast System (CFS). Combining both models into a multi-model ensemble yields superior forecast quality compared to either model individually.