The interannual variability of the Asian summer monsoon significantly impacts Asian society. While climate models predict the monsoon up to six months in advance, long-range prediction remains challenging. This study, using a 52-member large ensemble hindcast (1980–2016), demonstrates that a state-of-the-art climate model can predict the Asian summer monsoon and associated tropical cyclone activity more than a year ahead. Successful simulation of El Niño-Southern Oscillation (ENSO) evolution and the subsequent atmosphere-ocean response in the Indian Ocean-western North Pacific are key to this long-range prediction. A large ensemble size is crucial for achieving useful prediction skill.
