Hibernation, the beginning of the month of dao in the Dry Branches Calendar; dao, the month of mid-spring, the trigrams in the Zhen position, everything out of the Zhen, it is the phenomenon of the birth of the hair. A year twelve months to build, each month to build a corresponding hexagram, d month (including hibernation and the equinoxes of the two seasons) corresponds to the Leitian Dazhuang a hexagram; Dazhuang hexagram is the sky began to thunder, thunder in the sky ringing, very graphic. "Mao", the adventurous also, all things venture out of the ground, representing the vitality; so the month of Mao (February) is also the month of all things burst of energy, a year of spring plowing since the beginning.

When the hibernation season, spring is in full swing, and nature has a new vigor. The so-called "spring thunderstorm" refers to the time of the hibernation season, when spring thunderstorms begin to sound, awakening the stinging insects that lie dormant in the ground over the winter. The iconic feature of the hibernation season is the first movement of spring thunder, and everything is full of vitality. From China's natural climate, climate process, "hibernation began to thunder" only with some parts of the south of China's natural rhythms coincide.