Why is the south wind blowing in summer and the north wind blowing in winter?

The main reason is the pressure difference. Details are as follows:

Summer monsoon refers to the prevailing wind blowing from the ocean to the mainland in summer in monsoon region. In summer, the Asian continent is controlled by a huge thermal depression, and the ocean is in a state of high pressure, and the airflow blows from the high pressure area to the low pressure area. Located in the south of South Asia, Southeast Asia and China southwest depression, southwest monsoon prevails; Located in the east of China, the southeast monsoon prevails.

Winter wind: The specific heat capacity of land is less than sea level, so the relative sea level temperature is lower in winter, thus forming air flowing from the mainland to the ocean. Influenced by latitude and land and sea location, the prevailing wind direction in most parts of China changes significantly with the seasons in a year, forming a typical monsoon climate. The north wind often blows in winter.

Extended data:

Summer monsoon and winter monsoon:

China is mainly affected by winter and summer monsoon. In winter, the direct point of the sun is in the southern hemisphere, and the land temperature in the northern part of the Asian continent is extremely low in the high latitudes of the northern hemisphere, forming a high-pressure center inside and at home of the Mongolian people, which is called Mongolian high. Facing the Mongolian high, there are two low-pressure centers in the Pacific Ocean and the Indian Ocean, one is the Aleutian low and the other is the equatorial low. In winter, the general trend of air flow in China is that Mongolian high pressure flows to Aleutian low pressure and equatorial low pressure, forming winter wind.

The influence of winter monsoon on China is very extensive, with the southern boundary reaching the middle of the South China Sea and the western boundary located on the east side of the Qinghai-Tibet Plateau. Affected by the winter wind, the eastern part of China is cold and dry, sunny and rainy. In summer, the point of direct sunlight goes back and forth between the equator and the Tropic of Cancer, and the ground temperature rises due to direct sunlight, forming an Indian depression. Compared with land, the ocean temperature is lower, forming a subtropical high in the North Pacific Ocean, blowing to the mainland, southeast wind blowing in the east of China, and southwest wind blowing in the southwest frontier. The climate in the area affected by the summer monsoon is humid and rainy.

Baidu encyclopedia-summer monsoon

Baidu Encyclopedia-Winter Wind