Abstract: The work statistically studies the variations of the general circulation and external forcing factors in and before the extremely severe cold months. The result shows that the subtropical high in the west Pacific keeps weak or on an eastward or southward position in the current and previous 3 months. A weak summer monsoon in the previous year is accompanied by strong winter monsoon in the current year. The Asian polar vortex expands in the previous July, August and September and the current winter. There is less perpetual snow in the Tibetan Plateau in November and December prior to the current January. There is more sea ice in Region Ⅳ of the Arctic Ocean in the previous 11 months, especially March through August, prior to the current February. There is more polar ice in Region Ⅱ in January through November and less polar ice in Region Ⅲ in March through August prior to the current December. Integrating the preceding factors and previous characteristics of 500 hPa geopotenial fields and SST fields, a schematic predictive model is presented for extremely severe cold months in South China winter.