Solar terms and light snow, what does it mean to enter winter?

Because after the light snow, the northeast wind began to become a frequent visitor in China, and the temperature gradually dropped below 0℃, but the earth was not too cold. Although it began to snow, the amount of snow was not large, so it was called light snow. At this time, the yang is rising and the yin is falling, which leads to the impassability of heaven and earth, the imbalance of yin and yang, the loss of vitality of everything, the occlusion of heaven and earth and the turning into severe winter.