How was beginning of spring divided in ancient times?

In ancient China, the fifteen days in beginning of spring were divided into three periods: "The east wind thawed, the insects began to vibrate, and the fish began to get cold", which meant that the east wind warmed and the earth began to thaw. Five days after beginning of spring, hibernating insects slowly woke up in the cave. Five days later, the ice in the river began to melt and the fish began to swim on the water. At this time, there are still broken borneol on the water, floating on the water like fish. Since the Qin Dynasty, China has always regarded beginning of spring as the beginning of spring. Beginning of spring is divided from astronomy, but in nature and people's minds, spring is warm and flowers are fragrant. Spring is growth, cultivation and sowing. In climatology, spring refers to the period when the average temperature is between 10℃ and 22℃. Since the Qin Dynasty, beginning of spring has been the beginning of spring in China. Beginning of spring is divided from astronomy, but in nature and people's minds, spring is warm and flowers are fragrant. Spring is growth, cultivation and sowing. In climatology, spring refers to the period when the average temperature is between 10℃ and 22℃. 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. Irrigation and topdressing should be done in time to promote growth. Agricultural proverbs remind people that it rains in early spring, get up early and go to bed late. "Da Chun has also begun to prepare for farming. Although it is spring, most parts of South China are still very cold. " Spring snow comes too late, so it flies in the Woods. "... these climatic characteristics should be taken into account when arranging agricultural production. People often look for information about spring. The buds protruding from the wicker are "softer than gold and softer than silk"; The eager grass in the soil is waiting for "they grow taller in the spring breeze"; In order to win a new harvest, people who work hard in the fields are creating real spring with their hands.

Beginning of spring solar terms are also very popular among farmers, because they bring warmth and hope to people. Therefore, there are many weather proverbs about beginning of spring. For example, based on sunny days and no rain, there are "sunny days in beginning of spring, even if it rains" and "sunny days in beginning of spring, sunny days in spring". Based on rain and snow, there are "spring rains, rainy and wet, until sunny" and "Chun Xue raining and raining for a hundred days"; Based on thunder and lightning, there are "thunder represents the Spring Festival, and it never stops raining" and "spring thunder begins, and the sky is not seen in January". Based on the cold and warm, there is "cold in beginning of spring, warm in spring"; Based on the wind, there are "rainy north wind in beginning of spring", "early recovery of east wind in beginning of spring and late recovery of west wind in beginning of spring" and so on.