In mid-September, the air is cold and the dew condenses into frost. It describes the weather in mid-September, when the temperature begins to drop and the dew condenses into frost.
slight cold is one of the 24 solar terms, which usually occurs on January 5th or 6th every year.
in September, with the end of summer, the weather is getting cooler. The temperature difference between day and night began to increase, because the direct angle of the sun gradually decreased, which led to the decrease of heat received during the day. The night becomes colder, and dew begins to condense on grass leaves or branches, forming tiny ice crystals. These ice crystals sparkle in the morning sun, as if the whole world were inlaid with diamonds.
in the mild cold season, the weather is even colder. Although the sunshine can still bring some warmth at this time, the cold at night has become biting. People began to put on thick cotton-padded clothes to resist the cold weather. In the north, at this time, the river has been frozen thick, and people can slide freely on the ice. In the south, although the water is still not frozen, the river has become cold and no longer suitable for swimming.
In addition to the cold temperature, there are other phenological phenomena in the mild cold season. For example, plants begin to enter dormancy and grow slowly. Many animals also become less active, and some even go into hibernation. At this time, geese also began to migrate to the south, looking for a warmer climate.
The origin of the frost in September:
The phrase "the frost in September" comes from twenty-four solar term, an important document in ancient China. This book was written by Huang Chengxian of Ming Dynasty, and was written in the 23rd year of Wanli of Ming Dynasty (AD 1595). This book, which takes the moon as the key link, expounds the changing laws of astronomy, meteorology, phenology and agricultural activities on a monthly basis, and is one of the important classics of ancient agriculture and phenology in China.
In this sentence, the weather changes in mid-September are described by the fact that in mid-September, the air is cold and the dew condenses into frost. Specifically, Zhongqi refers to the white dew in the second solar term of the twenty-four solar terms. Su means that the weather has become cold and cold, and condensation into frost means that dew has condensed into frost. The whole sentence means that at this time of mid-September, the weather is getting colder and the dew has condensed into frost.
The weather change described in this sentence is of great significance in ancient China. On the one hand, it marks the deepening of autumn and the further reduction of temperature; On the other hand, it also indicates that the growth of crops has entered the last stage, and farmers need to seize the time to harvest crops to avoid being affected by natural disasters such as frost. Therefore, the phrase "it's cold in mid-September and condensed into frost" is not only a description of the weather change, but also a guidance and reminder for agricultural production.