What month are the big moon and the small moon?
The so-called big moon and small moon actually refers to the concept of the moon. 1 The average length of the moon is 29 days 12 hours, 44 minutes and 3 seconds, which is not an integer. The number of days in a month must be expressed as an integer. Therefore, people set the moon as 29 days and the moon as 30 days to make the average length of calendar months close to the moon.
In order to ensure that the first day of each lunar month must be the day of the new moon, the size of the month should be determined according to the number of days between the two new moons. The interval between two new moons is 30 days, which is a big moon, and the interval between two new moons is 29 days, which is a small moon.
The big moon and the small moon in the lunar calendar.
The lunar calendar takes a month as a unit, and a month begins on the day when the new moon appears and ends on the day before the next new moon appears. Because the period of the moon's revolution is between 29 and 30 days, a month in the lunar calendar is also 29 or 30 days from the appearance of the new moon. 30 days for the big moon and 29 days for the small moon.
Unlike the solar calendar, large and small months are not fixed in different years. For example, the day before the Spring Festival is usually called New Year's Eve, but in many years, such as the 2000 lunar calendar1February, there are only 29 days.