How are the four seasons divided?

Meteorological phenomena related to the four seasons include wind and light rain in spring, heavy rain and hail in summer, frost in autumn, snowfall in winter, etc.

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Four Seasons:

Spring ranks first among the four seasons, and a new cycle begins. Spring represents warmth, growth, budding plants, warm wind and warm sun, and the singing of birds and the fragrance of flowers. The temperature, sunshine, and rainfall in this season are at a turning point in the year and tend to rise or increase. In spring, the yin and yang qi begin to change, and all things sprout and grow as the yang qi rises. Spring is the season for the growth of all things and spring plowing and sowing. As the saying goes, "the plan for the year lies in spring." Spring

Start and end of spring:

Divided according to changes in celestial phenomena: Traditionally, the beginning of spring (Duzhiyin, when the sun reaches 315° of the Yellow Longitude) is the starting point of spring. , to the end of "Beginning of Summer".

Classification based on temperature changes: In modern times, the "climate average temperature" classification by scholar Zhang Baokun was adopted, and spring began when the climatology average temperature (the average temperature of five consecutive days) rose steadily from below 10℃ to above 10℃. , and ends when the average temperature is above 22°C (summer).

Summer

Summer is when everything flourishes and crops enter their peak growth season. The temperature rises, the weather is hot, storms occur frequently, and everything flourishes. Summer is the season with the most storms, often accompanied by strong winds and heavy rain. In the summer of the Northern Hemisphere, the heated air pressure on the continent rises to form low pressure, while the constant temperature of the ocean is relatively low and forms high pressure. According to the circulation, the southeasterly wind blows in summer. Summer has the longest daylight hours of the year across the Northern Hemisphere. [8]

Start and end of summer:

Divided according to changes in celestial phenomena: Taking "Beginning of Summer" (the bucket refers to the southeast, the sun reaches 45° of the yellow longitude) as the starting point of summer, to "The Beginning of Autumn" is over.

Divided based on temperature changes: Summer begins when the temporarial average temperature rises steadily above 22°C, and ends when the terrestrial average temperature rises below 22°C.

Autumn

Autumn is the harvest season, which means that all things begin to grow from lush growth to bleak maturity. The first two solar terms of autumn are Beginning of Autumn and End of Summer, which are still very hot weather. Because the heat brought by the sun has not weakened, the so-called "heat is in the three volts". The dog days appear between the minor heat and the end of summer. They are the highest temperature and humid in the year. , muggy days. The reason for the high humidity in Dog Days is that the southeast wind blows in Dog Days, and the Pacific and Indian Oceans are in the southeast. The air is moist, and the humidity of the wind causes high humidity in Dog Days. After late autumn, the opposite occurs, with northwest winds blowing, and the northwest is dry. Inland, dry northwest winds cause dry weather after late autumn. The climate characteristics of the first two solar terms in autumn are humid and sultry. The real coolness in autumn generally does not occur until after the Bailu solar term, and then gradually becomes cooler and drier. As we enter late autumn, the climate turns from hot to cool, and everything grows with the cold and gradually fades away. This is the season of alternating heat and cold. The most obvious changes in autumn are as the leaves of grass and trees turn from lush green to yellow, and as crops begin to lose their leaves, they begin to mature.

Autumn

The beginning and end of autumn:

Divided according to changes in celestial phenomena: "Beginning of Autumn" (the bucket points to the southwest, the sun reaches 135° of the yellow longitude) The starting point of autumn and the end of "beginning of winter".

Divided based on temperature changes: Autumn begins when the average temperature drops steadily from above 22°C to below 22°C, and ends when the average temperature drops below 10°C.

Winter

In winter, yin and yang change, all things are collected and stored, and the vitality of plants is stored. Entering the Beginning of Winter means that the drier and dry climate in autumn gradually passes and turns to rainy and cold winter climate characteristics. In the Northern Hemisphere, the height of the sun is small and the daylight hours are short. As the saying goes, "Hot comes in the third volt" and cold comes in the 39th. The winter solstice is "one-nine days". It is not very cold before the winter solstice. After the winter solstice, strong cold air moves south frequently and crosses the Nanling Mountains. The temperature drops sharply and the weather is cold. Winter is really cold after the winter solstice

The beginning and end of winter:

Divided according to changes in celestial phenomena: "Beginning of Winter" (the bucket points to the northwest, the sun reaches 225° of the celestial longitude). As the starting point of winter, it ends with the next "beginning of spring"

Based on temperature changes: winter begins when the average temperature drops steadily below 10℃, and ends when the average temperature drops above 10℃.