Abstract: In February 2022, southern China experienced persistent periods of cold, rainy, and snowy weather. The regional mean accumulated precipitation was 126.6 mm, marking a 99.7% increase compared with the multi-year (1981–2020) average. Additionally, the daily minimum temperature was 5.1°C, which was 2.6°C below the multi-year average. Analysis revealed that a particularly strong meridional wind vertical shear over southern China between 700 and 925 hPa was a key circulation feature in February 2022. The sea surface temperature (SST) anomalies related to the meridional wind vertical shear were analyzed, and the following results were obtained: Under the background of La Niña, the increase in SST over the tropical western Pacific and central North Pacific benefited the deepening of the East Asian trough and the occurrence of northerly wind anomalies in the lower troposphere over southern China. Furthermore, increased SSTs over the central North Atlantic Ocean strengthened the Ural Ridge and East Asia Trough through a Rossby wave train along the Western Europe–East Asia coast while enhancing the Siberian High and northerly winds in the lower troposphere over southern China. The increase in SSTs in the southeast Indian Ocean contributed to the strengthening of the southern branch trough and the anomalous anticyclone in the western North Pacific. These result in stronger southerly winds in the middle troposphere over southern China. The influence of SST exhibited sub-seasonal variations. SSTs in the central North Pacific and central North Atlantic showed significant correlations with the Siberian High in February, which is conducive to the lower temperature in February. The SST over the southern Indian Ocean was significantly correlated with the southern branch trough in January and February and the anomalous anticyclone in the western North Pacific in February. The increase in precipitation in southern China since mid-January was possibly related to the persistent warming of SST in this region. Consequently, SST anomalies in these areas might be associated with the sub-seasonal reversal from warm and dry conditions to cold and wet conditions during the winter of 2021/2022 and persistent cold, rainy, and snowy weather in February 2022.