When does the lunar calendar usually frost?

In a blink of an eye, today has reached 20 19, 10, 10, 24, the 26th day of the lunar calendar, which is what we often call the first frost today. There are many sayings and proverbs about the first frost in rural areas, the most famous of which is "there is no frost in early September and there is frost in early October".

The first frost is the first solar term after autumn. There is a saying that autumn is strong after the first frost, which means that the temperature will get lower and lower after the double drop, and this is the real autumn. Then there will be fog in the morning and frost on the ground after the first frost, so friends who want to go out in the morning must pay attention to safety. After all this nonsense, what did our ancestors mean when they said, "There is no frost in early September and there is frost in early October"?

There is no frost in early September.

The phrase "there is no frost in early September" means that if the first frost falls in September of the lunar calendar, there will be no frost in the morning after the frost. What the hell is going on here? It still has a lot to do with the temperature, because our country is located in a warm area, and the temperature is mainly affected by Mongolian high-pressure cold air and ocean hot air. If you want to turn into frost, the temperature should be at least very low, which will condense water vapor and water droplets into frost. However, in September when the first frost occurs, the temperature often fails to reach the critical point of low temperature at night, especially in areas with abundant water.

Early October frost

Because there is a certain gap in time between the solar calendar and the lunar calendar, this gap is not fixed in the 24 solar terms. If the first frost is in October, it is easy to say. Because October is called the winter month in our lunar calendar, as the name implies, it is the winter month, and the temperature drops obviously. Meteorologically, the Siberian cold current is dominant at this time, and it begins to oppress the ocean warm current from north to south. No matter where it goes, it is a cold image, which means the complete arrival of winter. At this time, a large amount of cold air will directly lead to a large-scale cooling across the country. If the temperature is low, it will naturally frost in the morning.

At the same time, the first frost is of great significance in agricultural production. Two-way means the final maturity of the fruits in the north, because the fruits will freeze to death and rot in the trees in the future. Friends who know fruit know that no matter what fruit it is, it is very sweet as long as it grows naturally in the first frost. For example, Aksu apples in Xinjiang, which are very famous in China, are only picked at the beginning of frost every year. At this time, Aksu apples in Xinjiang have already experienced the baptism of heavy snow, and they are crisp and sweet to eat. Moreover, heavy snow and thick frost will kill bacteria on the surface of apples, which is also an important reason why the supply of apples in Aksu, Xinjiang is in short supply every year.