What does the rainy season mean?

Meiyu period refers to a large-scale continuous rainy weather with frequent precipitation.

Meiyu period refers to the period of continuous rainy weather in the middle and lower reaches of the Yangtze River in China from mid-June to mid-July every year. At this time, the utensils are easily mildewed, so they are also called "mildew rain", and when the plums in the south of the Yangtze River are yellow, they are also called "plum rain" or "Huang Meiyu". The time that the rain belt stays is called "Meiyu season", the day when the rainy season begins is called "entering the plum blossom", and the day when it ends is called "emerging the plum blossom".

In the early summer (June-July) every year, there is a rainy weather with continuous heavy precipitation and frequent precipitation from the Jianghuai basin in China to southern Japan. It is named after the yellow ripe plums. Therefore, when the temperature is high, the humidity is high, there is a lot of rain, and the utensils are easy to get wet and moldy, hence the name mildew rain. Generally, plum blossoms enter plum blossoms from early June to mid-June, bloom from early July to mid-July, and begin in midsummer after flowering.

Climatic reasons

The formation of Meiyu is the result of long-term stagnation of cyclones or fronts in the local area. During May and June of each year, the subtropical high in the western Pacific is rapidly strengthened, and the hot and humid tropical marine air mass and equatorial air mass expand to Nanling area of China, and contact with the colder temperate air mass from the north to form a front. On the front, cyclones or troughs are constantly produced. When these cyclones or troughs move eastward, they are often blocked by the high pressure along the coast of China.

As a result, it moved slowly and stayed in the southeast hills, the middle and lower reaches of the Yangtze River and the southern part of the Huaihe River Basin for a long time, causing continuous rain and plum rains everywhere. The judgment of "entering Mei" needs to consider the actual weather (precipitation) and atmospheric circulation configuration. At present, in the weather forecast business of various provinces and cities, the date of plum blossom and plum blossom is mainly determined by local rainy days, rainfall, temperature and the location of subtropical high.

The above contents refer to Baidu Encyclopedia-Meiyu Period.