In February 2022, the southern China experienced persistent cold, rainy and snowy weather. The regional mean accumulated precipitation were 126.6 mm, 99.7% more than multi-year (1981~2020) average (63.4 mm), and the daily minimum temperature was 5.1°C, 2.6°C lower than the multi-year average. The analysis shows that particularly strong meridional wind vertical shear over southern China between 700 hPa and 925 hPa is a key circulation feature in February 2022. The related SST anomalies with the meridional wind vertical shear are analyzed. The results are as follows: Under the background of La Ni?a, the warming of SST over the tropical western Pacific and central North Pacific is beneficial to the deepening of the East Asian trough and northerly wind anomalies in the lower troposphere over southern China. The warming of SST over the central North Atlantic Ocean could reinforce the Ural Ridge and East Asia Trough through the Rossby wave train along the Western Europe-East Asia coast; strengthen the Siberian High and northerly winds in the lower troposphere over southern China. The warming of SST in the southeast Indian Ocean is conducive to the strengthened southern branch trough and western North Pacific anomalous anticyclone, which lead to the stronger southerly winds in the middle troposphere over southern China. The impact of SST has sub-seasonal difference. The SST over the central North Pacific and the central North Atlantic are significantly related to the Siberian High in February, which is conducive to the lower temperature in February. The SST over the southern Indian Ocean is significantly correlated with the southern branch trough in January and February, and western North Pacific anomalous anticyclone in February. The increase of precipitation in southern China from mid-January may be related to the persistent warming of SST in this area. Therefore, the SST anomalies in the above regions may be related to the sub-seasonal reversal from warm and dry to cold and wet in the winter of 2021/2022, and the persistent cold, rainy and snowy weather in February, 2022.