When is the rainy season?

Yesterday was the second of the 24 solar terms-rain, which represented the beginning of rain. As the saying goes, "Spring rain is as expensive as oil", and suitable precipitation is very important for the growth of crops. But in fact, although it was cloudy yesterday, it never rained. Although the rain will increase, it has not yet reached the rainy season. So, what month is the rainy season? Let's have a look!

When is the rainy season?

In China, the rainy season is from April to September in the south and from July to August in the north. The rainy season refers to the season of relatively concentrated precipitation in a year, that is, the wet rainy season with relatively concentrated precipitation every year. The precipitation in China is mainly brought by the southeast monsoon, so the precipitation in China is characterized by "decreasing from the southeast coast to the northwest inland" in geographical space.

The southeast monsoon brings water vapor to our country, and the southeast coastal area of our country will get the water vapor brought by the southeast monsoon first, forming rich precipitation, becoming the region with the richest annual precipitation in our country. Southwest monsoon also brings precipitation to China, which can affect South China. When the southwest monsoon develops strongly, it can also go deep into the Yangtze River basin.

Judging from the seasonal distribution of precipitation, precipitation in China is mainly concentrated in summer, that is, when the southeast monsoon prevails, so the climate characteristic of China is "the same period of rain and heat".

China belongs to a typical monsoon climate, and the rainfall area is mainly controlled by the atmospheric circulation system such as the subtropical high in the northwest Pacific. From mid-June to mid-July, the main rain belt in eastern China is generally lifted from South China and Jiangnan to the middle and lower reaches of the Yangtze River or Jianghuai area.

In late July, with the seasonal northward movement of the subtropical high circulation system, the southwest monsoon will also push northward. The southwest wind around the subtropical high will transport the tropical and subtropical warm and humid airflow to the northern region, where it will meet the cold air in the mid-latitude of North China and Northeast China, and North China and Northeast China will begin to enter the rainy season.