This study utilizes daily minimum temperature and relative humidity data from China’s CN05.1 dataset (1982–2022), along with ERA5 reanalysis data, to examine the spatiotemporal distribution characteristics and potential causes of two types of compound extreme low-temperature events in southern China during winter. The results indicate that cold–dry events are distributed across most of southern China, with high-frequency centers in the eastern and Jianghuai regions, whereas cold–wet events exhibit a south-to-north decreasing trend, occurring primarily in the southwestern and western South China regions. Over the past 41 years (1982–2022), cold–dry events have shown an increasing trend in most southern regions of China, whereas cold–wet events have significantly decreased, with notable interannual variability in both event types. Cold–dry events typically occur in early winter, while cold–wet events are more likely to occur in late winter. Further analysis of the different causes of these two event types reveals that early and late winter are associated with distinct atmospheric circulation systems and moisture conditions. The mid-to-high-latitude oblique ridge over Asia and the East Asian trough are key circulation features for cold–dry events, providing favorable conditions for the southward intrusion of cold air. During this period, pronounced moisture divergence over southern China promotes the occurrence of cold–dry events. In contrast, during cold–wet events, the northern branch of the wave pattern maintains a two-trough, one-ridge circulation over the middle and high latitudes of the Eastern Hemisphere. The southern branch of the wave pattern, propagating through West Asia and the Middle East, deepens the southern trough and interacts with the anomalous anticyclone over the western Pacific, transporting warm, moist air to southern China. This leads to moisture convergence in the region, providing abundant moisture for cold–wet events.