Why are there many rainy days in winter in South China in 2022?

In winter, there are many clouds in the sky, which are always gloomy and seldom sunny, especially in the south. The rainy weather in the south is mainly related to abundant water vapor transport in the south and frequent cold air activities in the north. Speaking of winter weather, the direct point of the sun moves to the south. Due to the thermal difference between land and sea, about 95% of the cold air in the northern hemisphere gathers in Siberia, and China is at the forefront of Siberia. When the cold wave broke out, the cold air moved rapidly southward, often passing through the North China Plain and southward to the middle and lower reaches of the Yangtze River.