How is the lunar calendar calculated?

A year in the lunar calendar has 12 or 13 months. The number of days in each month is determined according to the moon's orbit around the earth. It is 29 or 30 days. There are 13 months in a leap year. An average year in the Chinese lunar calendar is 353 or 354. There are 384 or 385 days in a leap year, and the average year is about 365.2422 days (that is, the time it takes for the earth to orbit the sun).

The lunar calendar basically has a cycle of 19 years. Since the lunar calendar year is about 355 days, which is about 11 days different from the earth year, a leap month must be set every 3 years, and a leap month must be set every 19 years. A leap month. Years with leap months are also called leap years. The specific leap month depends on the solar terms. For example, May 27, 2001, May 27, 1982 and May 27, 1963 in the Gregorian calendar are all leap days on the fifth day of April.

The month to which the leap month is added is inferred according to the rules of the lunar calendar, and is mainly determined based on the consistency with the twenty-four solar terms of the lunar calendar. Starting from the winter solstice, odd numbers are solar terms, and even numbers are mid-qi. If it is a month's turn that only has solar terms but no mid-qi, it is the leap month of the previous month. ?The number of days in a leap month in the lunar calendar is the same as the number of days in a normal month, which is 29 or 30 days.

Extended information:

Advantages of the lunar calendar:

1. The lunar calendar is a fixed calendar. It has the characteristics of an astronomical calendar and can integrate well with various celestial phenomena. Correspondence, for example, its solar terms strictly correspond to the height of the sun, calendar days strictly correspond to the phases of the moon, the non-occurrence frequency and occurrence frequency of leap months correspond to the perihelion and aphelion of the earth, and other celestial phenomena such as sunrise and sunset, morning and dusk shadows, and five stars. Orientation, solar and lunar eclipses, tides, etc., even the calendar month roughly corresponds to the height of the sun;

2. The number of days in the lunar calendar month is only 29 and 30, and is determined by the fixed day, human factors The smallest and not easy to change at will;

3. The beginning of the year has strong astronomical significance and has the astronomical significance of the lunar, lunar and yang years;

4. The lunar and yang calendar best reflects the Han nation The traditional culture of the unity of man and nature and the harmony of yin and yang;

5. The chronology of the stems and branches and the chronology of the twelve zodiac signs are used cyclically; because it contains solar terms, it is very conducive to the division of the four seasons, and because it contains the moon phases, it also reflects the tides. , solar and lunar eclipses and other celestial phenomena and the influence of the moon on climate.

Lunar calendar (traditional Chinese calendar)-Baidu Encyclopedia