Summer Solstice

At the Winter Solstice, yang qi has just begun to return, but yin qi remains dominant. Earthworms curl tightly together within the frozen soil, remaining contracted rather than stretching out as they endure the coldest period of the year.

The milu deer is traditionally regarded as an animal associated with yin. At the Winter Solstice, when “one yang is born”, it is believed to sense the first stirring of yang qi and begin shedding its antlers, forming a yin-yang counterpart to the Summer Solstice phenomenon of “鹿角解.”

As yang qi is first reborn at the Winter Solstice, underground springs begin to stir faintly in the depths of the earth. Although the surface remains sealed by ice, beneath it the first message of spring is already being prepared.

Sea-surface temperatures across the tropical Northern Hemisphere reach their annual maximum, and the number of tropical cyclones—typhoons and hurricanes—also reaches a peak. The northwestern Pacific enters its period of highest typhoon frequency.

Nourished by abundant rainfall, tropical rainforests in the Northern Hemisphere reach their lushest and most luxuriant state of the year, while the vitality of biodiversity rises to its annual peak.

Signs of the transition between dry and wet seasons become increasingly apparent across tropical regions of the Southern Hemisphere. Rainfall begins to increase in some areas, and vegetation enters a preparatory phase for a shift in its seasonal growth pattern.