Reflect the temperature changes of solar terms are

The solar terms reflecting the temperature change are introduced as follows:

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, Changsha, beginning of autumn and beginning of winter are called "Li Si", 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. Speaking of beginning of spring, people obviously feel that the days are getting longer and the sun is getting warmer. Temperature, sunshine and rainfall are often at the turning point of the year and tend to rise or increase. The growth of crops in early spring is accelerated, and the water consumption for bolting rape and jointing wheat is increased.

Long summer: 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 in summer is higher than 22℃, the southern Sichuan basin just entered summer before and after the long summer; The temperature in other basins is about 20℃, and it is still in the late spring season when "there is no one outside to ask the flowers to fall, and Ran Ran is covered with greenery"; The low-altitude valley in southwest Sichuan felt the heat in summer as early as mid-April, and the temperature in long summer was above 24℃.

Third, beginning of autumn: After beginning of autumn, at the jointing and booting stage of late rice in Sichuan Basin, cotton bolls cracked and vomited; 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 behind beginning of autumn, although the season is still midsummer, there will soon be a golden "autumn" in which "beginning of autumn is full of yellow in ten days".

Beginning of winter: It means that winter has begun. On that day in beginning of winter, the water began to freeze and the ground began to freeze. People often take the cold north wind and cold frost and snow as symbols of winter. In the later period of beginning of winter, strong cold air attacks more, and the temperature often drops greatly. In some years in the northwest of the basin, there is early frost in early winter. At this time, the plateau area is already in the dry season, the humidity decreases rapidly and the wind speed increases gradually.

Extended data:

First, solar terms reflecting temperature changes.

There are five solar terms: slight summer heat, great summer heat, summer heat, slight cold and great cold.

Second, solar terms reflecting weather phenomena.

Rain, Grain Rain, White Dew, Cold Dew, First Frost, Light Snow and Heavy Snow are the seven solar terms.

Third, solar terms reflecting phenological phenomena.

Four solar terms: Sting, Qingming, Xiaoman and Mangzhong.

The origin of solar terms

The ancients in China divided the sun's annual trajectory into 24 equal parts, each of which was divided into a solar term, and each solar term had three cycles, each of which was five days. According to the law of the operation of heaven and earth, the ancients determined the starting point and ending point of the four-season cycle and divided the 24 solar terms. The trajectory of the sun in a year is divided into 24 equal parts, each of which is a "solar term", collectively called "twenty-four solar terms".