How are the four seasons distinguished (or defined), and where are the intersections of the four seasons? Are all countries in the world divided in this way?

1. China and the west divide the four seasons differently. The method of dividing four seasons in China emphasizes the astronomical characteristics of seasons: summer is the season with the longest day and the highest sun at noon; Winter is the season with the shortest day and the lowest sun at noon. Spring and autumn is the transitional season between winter and summer, with uniform day and night and moderate sun height at noon. Specifically, the "Sili" (beginning of spring, Changxia, beginning of autumn, beginning of winter) in the 24 Qi is taken as the beginning and end of the four seasons, which is divided into two parts and four parts (see the division of the four seasons).

Spring: beginning of spring is the starting point, beginning of spring is the midpoint, and the long summer is the end point;

Summer: Long summer is the starting point, summer solstice is the midpoint, and beginning of autumn is the end point;

Autumn: beginning of autumn is the starting point, autumn is the midpoint, and beginning of winter is the end point;

Winter: beginning of winter is the starting point, the winter solstice is the midpoint, and beginning of spring is the destination.

Such four seasons have obvious astronomical significance, but they are inconsistent with the actual climate. For example, beginning of spring and beginning of autumn are the beginning of spring and autumn, but the climate is still in the middle of winter and summer; Summer solstice and winter solstice are the midpoint of summer and winter, but in climate, they are not the hottest and coldest times of the year.

Twenty-four Qi is a summary of long-term astronomical, meteorological and phenological observations of working people in China, and it is a great scientific achievement in ancient China. Its division has the characteristics of astronomical season and climatic season. It is divided into four parts (collectively called eight paragraphs) to express the astronomical season; The gases such as rain, fright, Qingming, Grain Rain, Xiaoman, Mangzhong, Slight Summer, Great Summer, Early Summer, White Dew, Early Frost, Light Snow, Heavy Snow, Slight Cold and Severe Cold clearly indicate the climate and farming season. Among them, the great summer heat and the great cold represent the hottest season and the coldest season in a year respectively. Summer is the second qi after the summer solstice, that is, one month after the summer solstice, which is roughly equivalent to the middle volt in the traditional "three volts"; Great cold is the second breath after the winter solstice, that is, one month after the winter solstice, similar to the traditional "March 9". Therefore, there is a folk saying that "the cold is in the March 9th and the heat is in the middle". Astronomical season and climatic season are obviously different and closely combined.

The division of four seasons in the west focuses more on climate. It takes bisection as the starting point of the four seasons. These four seasons are one and a half months later than the astronomical season in China. For example, the month and a half from beginning of spring to the vernal equinox is the first half of spring in China, but the second half of winter in the west.

Both the four seasons in China and the four seasons in the west are divided into two halves, which have exact astronomical significance. These two methods are astronomical, and it is impossible to fully consider the characteristics of climate. According to the definition of astronomy, a year is divided into four roughly equal seasons; In the same season, different latitudes have the same consistency. In climate, the length of four seasons is not necessarily equal; In the same season, different latitudes will have different durations.

In order to make the four seasons reflect the climatic conditions on the ground, we must use the standard of climate itself to divide the four seasons. Climatology usually takes the average humidity (average temperature every five days) as the division standard of seasons: the period when the weather temperature is higher than 22℃ is summer, the period when it is lower than 10℃ is winter, and the period between them is spring and autumn. In this way, there are the same temperature standards in spring, summer, autumn and winter. However, in the same place, the four seasons must be different in length; Different places, the same season is not always the same. Moreover, there are not four seasons everywhere.

2. A year is 12 months, and every quarter is three months. According to the different temperatures, people call March, April and May spring. June, July and August are designated as summer, and September, 65438+ 10, 165438+ 10 are designated as autumn. 65438+February, 65438+ 10 and February are designated as winter. China is a vast country with thousands of kilometers between north and south. Therefore, it is the same season, but the temperature is very different. For example, in spring, the southernmost part has put on summer clothes, and the northernmost part is still wearing cotton-padded clothes.

Please adopt it.