Abstract:This study uses observation data from stations in the eastern Southwest China and ERA5 reanalysis data and analyzes the characteristics and causes of the inverse phase shift anomalies in winter temperatures (referred to as anomalous shifts) in this region. The findings indicate that after 2000, this region tended to experience a pattern of colder temperatures earlier in the winter followed by warmer temperatures later (referred to as P1 type), whereas a pattern of warmer temperatures followed by colder ones (referred to as P2 type) was more prevalent in the 1970s. During the occurrence of these anomalous shifts in winter temperatures, the 500 hPa geopotential height field reveals that the Tibetan Plateau plays a cru-cial role in the circulation system, even surpassing the influence of the Ural blocking high. At the 200 hPa wind field, systems such as the westerly jet stream affect the East Asian winter monsoon influencing the intra-seasonal variation of temperature in winter. In terms of sea-level pressure fields, when the Mongolian high exhibits significant weakening after an initial strengthening in winter, P1 type temperature shifts are more likely to occur, and vice versa for P2 type shifts. Additionally, during these anomalous temperature shifts within the winter season, significant anomaly signals have been observed in the North Atlantic, the equatorial central and eastern Pacific and the equatorial Indian Ocean. High sea surface temperature anomalies in these three areas during the preceding summer and autumn seasons tend to cause P1 type shifts in winter temperatures, whereas the opposite conditions tend to result in P2 type shifts. Thus, abnormal sea surface temperature can serve as potential precursors for prediction.