According to the Guangzhou Wuyang Planetarium, last year's winter solstice day was December 21; this year's winter solstice day is also December 21. The winter solstice date for two consecutive years is December 21, which is a very rare calendar phenomenon. According to statistics, this strange calendar phenomenon last appeared in 1896 and 1897, 124 years ago.
Why is this calendar phenomenon? The main reason is that the length of the current solar calendar is inconsistent with the length of the regression year. The twenty-four solar terms are based on the length of one year of the year of return. The length of one year of the year of return is 365.2422 days. The current date of the solar calendar is a cycle of 4 years (in the range of decades), of which there are three years of days, 365 days per year; there are 366 days of one year (leap years), a total of 1461 days in four years. The length of the 4 years of the regression year is: 365.2422 ×4 = 1460.9688 days. The difference between the two is 0.0312 days. That is, the length of the 4-year solar calendar date is 0.0312 days more than the length of the 4-year return year. As time goes by, the solar term (winter solstice) date will arrive early. With the postponement of time, the trend of early solar terms (winter solstice) dates is becoming more and more obvious.
According to statistics, from 2056 onwards, for three consecutive years (2056-2058), the winter solstice date is December 21. What is even more unusual is that from 2088 onwards, for 12 consecutive years (2088-2099), the winter solstice date is December 21.
This year's "winter solstice" solar terms occur at 23:59 on December 21, the moment when the sun reaches 270 degrees of ecliptic longitude, and the sun directly hits the Tropic of Cancer. The Northern Hemisphere has the shortest days and the longest nights. On the day of the winter solstice, the sunrise in Guangzhou is 7:04 and the sunset is 17:46; the sunrise in Shenzhen is 6:59 and the sunset is 17:44.
Source: China News Network
