"There is a magpie bridge, and a thousand jade pendants have passed Lingling." August 22 ushered in the annual Qixi Festival, also known as the Cowherd and Weaver Girl Festival. Some people found that this year's Qixi Festival came a little late. What's the matter? Qixi is the seventh day of July in the lunar calendar, but the corresponding date in the Gregorian calendar is not fixed, usually between the late July and the early August of the Gregorian calendar. This year is the "leap year" of the lunar calendar, with an additional "leap second month", which starts on March 22 and ends on April 19 of the Gregorian calendar. It is precisely because a month was inserted before the lunar July that the day of Qixi was postponed. Why should we set up leap months? Yang Jing, a member of the Chinese Astronomical Society and a member of the Tianjin Astronomical Society, introduced that there are currently two calendars in China: the Gregorian calendar and the Lunar calendar. The length of a Gregorian year is 365 days or 366 days, and the length of a Lunar year is 354 days or 355 days, with a difference of about 11 days between the Gregorian and Lunar calendar years. To balance the "time difference" between the two, the lunar calendar adopts the method of adding leap months and sets the rule of "seven leap months in nineteen years". Every 2 to 3 years, an additional month must be added, which is called a "leap month". The rule of 'intercalation' is determined based on the 24 solar terms. According to the lunar calendar, each lunar month has a neutral energy. If a month does not include neutral energy, it is considered a leap month from the previous month. March 21st of this year (the 30th day of the second lunar month) is the mid air vernal equinox, and the next mid air valley rain is on April 20th (the first day of the third lunar month). Among them, there is only one clear solar term from March 22nd to April 19th in the lunar month, without mid air, so this lunar month is designated as a leap month. Because it is preceded by February, it is called "leap February". It is precisely because of the "extra" of this "leap February" that this year's Qixi came a little late. Yang Jing pointed out that leap months often occur from April to August, with few occurring in February, March, September, and October, while January, November, and December are extremely rare. Is Qixi the latest festival this year? No! The statistical results of the 200 years from 1901 to 2100 show that the Gregorian calendar date corresponding to Qixi can be set as early as July 31 (such as 2006) and as late as August 30 (such as 1987), which also means that any day from July 31 to August 30 in the Gregorian calendar may become Qixi. According to this, this year's Qixi Festival is not too late. Yang Jing said that in the same way, this year's Dragon Boat Festival, the upcoming Mid-Autumn Festival and the Double Ninth Festival will be relatively late, 19 days later than last year. (New News Agency)