The predictability of East Asian winter (December-January-February; DJF) monsoon (EAWM) index and South China winter rainfall, and the relationship of South China winter rainfall with the EU pattern have been investigated in this study.A comprehensive assessment of the seasonal predictability of East Asian winter monsoon index and South China rainfall has been performed using the 1-month lead retrospective forecasts (hindcasts) of five state-of-the-art coupled models from Ensembles-Based predictions of Climate Changes and Their Impact (ENSEMBLES) for the period of 1961-2006.The predictability of the EAWM and South China rainfall originates from their relationship with ENSO.However,interannual variability in South China winter rainfall is found to be associated with the extratropical circulation anomalies, particularly EU pattern, which is unpredictable.　　1.Predictability of the East Asian winter monsoon indices by the coupled models of ENSEMBLES　　The ENSEMBLES models well predict the five EAWM indices, with temporal correlation coefficients ranging from 0.54 to 0.61, out of the 21 indices examined in this study.These five indices are defined by averaged lower-tropospheric winds over the low latitudes (south of 30°N).Further analyses indicate that the predictability of these five indices originates from their intimate relationship with ENSO.A cross-validated prediction which takes the preceding (November)observed Ni(n)o 3.4 index as a predictor gives a prediction skill almost identical to that shown by the model.On the other hand, the models present a rather low predictability for the other indices and for the surface air temperatures in East Asia.In addition, the models fail to reproduce the relationship between the indices of different categories, implying that they cannot capture the tropical-extratropical interaction related to the EAWM variability.These results suggest that reliable prediction of overall the EAWM indices and East Asian air temperature is still a task of full challenge.　　2.Predictability of winter rainfall in South China as demonstrated by the coupled models of ENSEMBLES　　Winter rainfall over South China shows strong interannual variability, which accounts for about half of the total winter rainfall over South China.It was found that the ENSEMBLES models predicted the interannual variation of rainfall over South China well, with the correlation coefficient between the observed/station-averaged rainfall and predicted/area-averaged rainfall being 0.46.In particular, above-normal South China rainfall was better predicted, and the correlation coefficient between the predicted and observed anomalies was 0.64 for these wetter winters.In addition, the models captured well the main features of SST and atmospheric circulation anomalies related to South China rainfall variation in the observation.It was further found that South China rainfall, when predicted according to predicted DJF Ni(n)o3.4 index and the ENSO-South China rainfall relationship, shows a prediction skill almost as high as that directly predicted, indicating that ENSO is the source for the predictability of South China rainfall.　　3.Winter rainfall over South China in association with the Eurasian teleconnection pattern and ENSO　　The relationships of South China winter rainfall with both the EU pattern and ENSO, and their decadal variability for the period of 1961-2006 are investigated.The EU pattern and ENSO have an intimate relationship with South China rainfall,with correlation coefficients being 0.54 and 0.51.Although both of them have a close relationship with South China rainfall, they have differences in their anomalous features related to South China rainfall.For instance, atmospheric circulation anomalies associated with South China rainfall shows a great similarity with those of the EU pattern in the extratropics and those of ENSO in the tropics.The EU pattern shows a close relationship with rainfall over eastern China including South China,whereas ENSO is closely connected with only South China rainfall.Furthermore, the EU pattern is related to South China rainfall when the South China rainfall anomalies are negative regardless of El Ni(n)o year, whereas ENSO has relevance to South China rainfall when the South China rainfall anomalies are positive or El Ni(n)o year.However, the EU pattern and ENSO show a very weak connection, with correlation coefficient being 0.20, indicating that they affects the interannual variation of South China rainfall independently of each other.In addition, the relationships of South China rainfall with the EU pattern and ENSO show decadal changes: The EU pattern is overwhelmingly related to all eastern China rainfall includingSouth China rainfall before the middle of 1970s and ENSO is greatly related to only South China rainfall after the early of 1990s.