Why is the winter solstice the longest day in a year?

Yes, strictly speaking, the days are getting longer and longer after the solstice in winter. A few minutes a day is not fixed. Related to the day; It is also related to your latitude.

"After winter, a needle grows", "After eating the winter solstice meal, a thread grows every day". From the winter solstice, the direct sunlight position moves northward, and the daytime gradually extends, with an average daily increase of more than 90 seconds, that is, 1 min 30 seconds.

Winter solstice phenology:

The ancients in China divided the winter solstice into three stages: "One stage is earthworm knot; Second, wait for the elk horn to solve; Waiting for the spring to gush out. " Legend has it that earthworms are creatures with yin bending and yang stretching. At this time, although the yang has increased, the yin is still very strong, and the earthworms in the soil are still curled up.

Elk and deer belong to the same family, but yin and yang are different. The ancients thought that the elk's horns were facing the afterlife, so they were cloudy, and the winter solstice was born in the sun. The elk felt that the yin gradually receded and solved their horns. Because of the birth of yang, the spring water in the mountain can flow and be warm at this time.