How to calculate leap month? How many years is a leap year?

First, the leap month calculation method

Leap moon refers to a phenomenon in the lunar calendar. The lunar calendar arranges the big moon and the small moon, that is, the moon, according to the moon's round and round. The length of a moon is 29.5306 days, so the big moon is 30 days and the small moon is 29 days. This is the cycle of moon phase profit and loss.

In the lunar calendar, the length of the first month of the lunar calendar (29.5306 days) is the average of one month, and the whole year is 12 months, which is about 18 days and 2 1 hour in the tropic year (365.2422 days), so we should set leap, one month for three years, two months for five years and nineteen.

Second, there will be a leap every four years. Divide the year of the current year by 4, the year without remainder is leap year, and the year with remainder is average year.

A leap month is a way to set a leap month in a calendar. In Asia (especially in China), leap month refers to one month added every leap year in the Chinese calendar (also known as the lunar calendar) (in order to coordinate the contradiction between the tropic year and the Chinese calendar and prevent the tropic year from being out of touch with the four seasons, 1 leap is set every two to three years. In ancient times, 19 leap week was used, but it was abolished in Linde calendar of Tang Dynasty. Sometimes leap month also refers to the month that contains leap day in leap year of Gregorian calendar (that is, February of leap year of Gregorian calendar).

If you don't pay attention, probably many people think that "leap month" and "leap year" are the same meaning, but they are not. Although there is only one word missing, the meaning is far from the same.

What we usually call a "leap year" of 365 days a year is actually a rough figure, and the exact figure should be 365.2422 days. Then 365 days a year is 0.2422 days less than the actual year, and then four years later it is nearly one day less than the actual year. In order to make up for this difference, the calendar stipulates that four years is a leap year, that is, a year divisible by four is a leap year. In addition, it is stipulated that every century year (the year with two zeros at the end) must be divisible by 400 to be a leap year, and other hundred years are not leap years, that is, "there is no leap in a hundred years". For example, 1996 is a leap year, and 2000 is also a leap year, but 1700 is not. The leap year in the solar calendar has 29 days in February, the leap day is February 29 and the leap year in the solar calendar has 366 days. In other words, February in a leap year in the solar calendar is not called leap February. It is said that "leap moon" is unique to yin and yang calendars (Han calendar, Tibetan calendar, etc.). ).

Many people have misunderstandings about the lunar calendar in China, and often confuse the lunar calendar with the lunar calendar.

There are three calendars in the world: one is the solar calendar, which means that the time for the earth to make a circle around the sun is one year, and the number of months and days in a year can be specified artificially; One is the lunar calendar, in which the time for the moon to circle the earth is one month, and only a few months in a year can be designated artificially; The third is the lunar calendar, that is, the average time for the moon to go around the earth is January, but by setting leap months, the average number of days in a year is equal to the average time for the earth to go around the sun, such as the Chinese calendar and Tibetan calendar.

So China's Han calendar is not a lunar calendar, but a yin-yang calendar.

The lunar calendar and the solar calendar in the Han calendar have their own uses. The lunar calendar can indicate the moon's profit and loss, and can also predict the tides.

Lunar calendar is more useful. Twenty-four solar terms are a great invention in ancient China. It shows the position of the earth in orbit, reflects the annual apparent movement of the sun, and is most suitable for guiding agricultural activities. Therefore, the traditional lunar calendar in China is called the lunar calendar. Therefore, the lunar calendar is different from the lunar calendar, and it is not appropriate to call the lunar calendar the lunar calendar.