Abstract:Anomalies of oceanic and atmospheric circulations are analyzed and their impacts on temperature and precipitation anomalies of 2015 in China are investigated in this paper. It is found that the East Asian Winter Monsoon (EAWM) was weaker than normal during the 2015 winter with an obvious phase transition from the strong to the weak at the end of December 2014. A warmer winter was experienced in most areas of China due to the effect of weaker EAWM. In association with the phase transition of EAWM, a reverse of temperature anomalies over China occurred simultaneously with negative temperature anomalies in December 2014 and positive temperature anomalies in January and February 2015. A super strong El Ni〖AKn~D〗o event occurred over the tropical Pacific Ocean, with the accumulative Ni〖AKn~D〗o Z index from May to November 2015 reaching to 23.0℃, was the strongest event on record. In addition, the remarkable Indian Ocean basin wide warming mode and the dipole mode with positive phases persisted since April of 2015. As a response of atmospheric circulation to the anomalous tropical oceanic condition, the western Pacific subtropical high intensified and extended further southward and westward, leading to less precipitation over North China and more precipitation over South China during summer. In 2015, onset of South China Sea summer monsoon was near normal and the ending time was 2 pentads later than normal with the intensity being weaker than normal.