Which solar term is short days and long nights?

Short days and long nights are the solstice of winter. The winter solstice is around 65438+February 2 1 in Gregorian calendar. On the solstice of winter, the sun shines almost directly on the tropic of Capricorn, and the northern hemisphere has the shortest day and the longest night, and it begins to enter several cold days. Astronomy stipulates that this day is the beginning of winter in the northern hemisphere. From winter to the future, the direct sunlight position gradually moves northward, and the daytime in the northern hemisphere gradually becomes longer.

The winter solstice is the most important day among the 24 solar terms, and it is also the most important day in a year considered by the ancients. The ancients used sunlight to measure the shadow of the sun. It was found very early that the shadow of the sun was the longest on this day, so it was the easiest to correct it from this day. Therefore, the ancients took the winter solstice as the beginning of the year.

In the Zhou Dynasty, the month of winter solstice is January, and the first day of the first month refers to the day when the new moon was born, which is the beginning of the year. At that time, the Zhou Dynasty had adopted the earth branch to record the month, and the month of the winter solstice was the second month, which is now 1 1 month in the lunar calendar.