What is the sign of summer?

The standard for entering summer is that the average temperature is ≥22℃ for five consecutive days. In China, summer begins with a long summer and ends in early autumn. In some areas of China, it is from the solstice to September in summer, and there are certain differences between the north and the south. Fujian and Guangdong usually end at the autumnal equinox. The middle and lower reaches of the Yangtze River reach high temperature in summer, while the northern region begins in autumn.

In the traditional method of dividing the four seasons in ancient China, according to the change of astronomical phenomena, the "Li Si" in the 24 solar terms was taken as the starting point of the four seasons. At present, the four seasons are often divided by the change of temperature, and are divided by the "average temperature" of modern scholar Zhang Bao _. That is, the average temperature in winter is less than10℃; Spring10 ~ 22℃; Summer ≥ 22℃; In the autumn of 22 ~ 10℃, this classification of four seasons based on temperature change is more suitable for mid-latitude temperate regions with large temperature difference and obvious seasonal temperature change. This is the current division of the four seasons from the perspective of climate change, and it is also recognized by the meteorological community as a standard for the division of the four seasons.

"Climate average temperature" four-season division index: winter is when the climate average temperature is less than 10℃; Summer is when the average temperature is greater than 22℃; Average temperature in spring and autumn 10℃ ~ 22℃. There is also an astronomical method to divide the four seasons, that is, March to May is spring, June to August is summer, September to 165438+ 10 is autumn, and 12 is winter.