How many of the 24 solar terms reflect the changes of the four seasons?

The solar terms reflecting the changes of the four seasons are: beginning of spring, Spring Equinox, long summer, Summer Solstice, beginning of autumn, Autumn Equinox, beginning of winter and Winter Solstice. Among them, beginning of spring, long summer, beginning of autumn and beginning of winter are called "Sili", which means the beginning of the four seasons.

1. beginning of spring: beginning of spring is divided from astronomy, and the starting time is usually February 3-5. When it comes to beginning of spring, people obviously feel that the days are getting longer and the sun is getting warmer. Temperature, sunshine and rainfall, which are often at the turning point of the year, tend to rise or increase. The growth of crops in early spring is accelerated, and the water consumption of rape bolting and wheat jointing is increased.

second, long summer: it refers to the beginning of summer. However, the temperature varies from place to place, and the time of entering summer is actually inconsistent. According to the climatological standard that the five-day average temperature is higher than 22℃ in summer, before and after long summer, the southern Sichuan Basin just entered summer; The temperature in the rest of the basin is about 2℃, and it is still in the late spring season of "no one asks the fallen flowers outside the door, and the green shade of Ran Ran is all over the world"; However, the low-altitude valley in southwest Sichuan felt hot in summer as early as mid-April, and the temperature in long summer was above 24℃.

Third, beginning of autumn: After beginning of autumn, late rice in Sichuan Basin started jointing and booting, and cotton bolls cracked and bolled; Mid-season rice and summer corn enter the stage of filling maturity to prevent the harm of hail, strong wind and heavy rain. In the basin after beginning of autumn, although the season is still midsummer, there will soon be a golden "autumn" of "beginning of autumn is full of yellow in ten days".

4. beginning of winter: It means that winter begins. "On the day of beginning of winter, the water began to freeze and the ground began to freeze". People often take the chilly north wind and the cold frost and snow as the symbols of winter. In the later period of beginning of winter, there are many strong cold air attacks, and the temperature often drops greatly. In some years in the northwest of the basin, there was early frost in beginning of winter. At this time, the plateau area is already a dry season, with the humidity rapidly decreasing and the wind speed gradually increasing.

Extended information:

1. Solar terms reflecting temperature changes

There are five solar terms: Slight summer, Great summer, Chu summer, Slight cold and Great cold.

second, solar terms reflecting weather phenomena

There are seven solar terms: rain, Grain Rain, Bailu, cold dew, first frost, light snow and heavy snow.

Third, solar terms reflecting phenology

Four solar terms, namely, fright, Qingming, Xiaoman and Mangzhong

The origin of solar terms 4 and 24

The ancient people in China divided the annual movement track of the sun into 24 equal parts, each of which is a solar term, and each solar term has three periods, each of which is five days. The ancients determined the starting point and ending point of the four-season cycle and divided the 24 solar terms according to the law of the operation of heaven and earth. The annual movement track of the sun is divided into 24 equal parts, and each equal part is a "solar term", collectively called "24 solar terms".

China net-the origin of the twenty-four solar terms.