The difference between first frost and the first frost.

Frost is a special kind of water vapor condensed, and it appears on a clear moonlit night in autumn. There is a lot of heat dissipation on the ground in autumn nights. When the temperature suddenly drops below 0℃, the water vapor in the air directly condenses on the ground or plants to form fine ice needles, and some become hexagonal frost flowers with white color and loose structure. This white crystal is "frost".

The first frost is the18th solar term among the 24 solar terms, and it is also the last solar term in autumn. The sun reaches the longitude of 2 10 degrees, and meets on the 23rd and 24th of October in Gregorian calendar 10/.

Climatic characteristics of the first frost solar terms

In ancient China, the first frost was divided into three stages: "One stage was that the jackal sacrificed animals; Second, the vegetation is yellow; Three waiting insects are salty. " This means that in the solar term of the first frost, the jackal will show his prey first and then eat it; The leaves on the earth turned yellow and fell; The stinging insects are motionless in the cave, hanging their heads and going into hibernation. "The first frost in the first frost" reflects the climate characteristics of the Yellow River Basin.

The solar term of the first frost means that the weather is getting colder and first frost begins. To the south of latitude, the average temperature is around 16℃, and there are three solar terms before the first frost day. In the southern valley of South China, frost can only be seen in the dead of winter.

Of course, even at the same latitude, the temperature and humidity of the air close to the stratum are different due to the difference of altitude and topography, and the first frost period and frost day are also different.