What does the first frost of the twenty-four solar terms mean, the first frost of the twenty-four solar terms?

1 .24 The cold first frost in the Song Dynasty refers to: cold dew-cold dew, and the first frost means' first frost'.

2. Twenty-four solar terms refer to the special festivals in the dry calendar that indicate seasons, phenology, climate change and the establishment of "December construction".

3. Initially determined by the bucket handle direction of the Big Dipper, bucket handle rotates around the east, south, west and north, which is called one of the "years old" (Figure); Every rotation cycle starts from beginning of spring and ends with the Great Cold.

4. The current "twenty-four solar terms" are divided by "constant gas method", that is, each solar term corresponds to a certain position that the earth reaches every time it runs 15 on the ecliptic; The method of "fixing qi" divides the sun's annual movement track into 24 equal parts, each equal part is 15, and each equal part is a solar term, which starts from beginning of spring and ends with severe cold.