Meiyu area is located at the edge of subtropical high and appears in Jianghuai area of China from mid-June to early July every year.

The subtropical high in the western Pacific has an important influence on the weather and climate in China, especially the high ridge in the west goes deep into China, which affects the rain belt in China.

In the middle and late June, the subtropical high ridge in the western Pacific jumped northward, stabilized at 20 ~ 25 north latitude, and the rain belt moved northward, and the middle and lower reaches of the Yangtze River entered the rainy season, that is, Meiyu;

In early and middle July, the ridge line of subtropical high jumped northward again, swinging at 25 ~ 30 north latitude, and the lower reaches of the Yellow River entered the rainy season.

Meiyu in the middle and lower reaches of the Yangtze River ended and entered midsummer. Due to the control of high pressure ridge, summer drought appeared.

Pay attention to the stability (between 20 and 25 north latitude), the rain belt will move northward, and the middle and lower reaches of the Yangtze River will enter the rainy season, which is plum rain.

Jianghuai area is located in Jiangsu Province, China, south of Huaihe River in Anhui Province and along the lower reaches of Yangtze River.

20 ~ 25 degrees north latitude.

Only the ridge of high pressure in the west affects China, and the subtropical high in the western Pacific is mainly in the western Pacific.

So this is the northwest edge.