The solar calendar is also the Gregorian calendar, which is internationally accepted. The Gregorian calendar is customized based on the time that the earth revolves around the sun for one year, ***365 days, 5 hours, 48 minutes and 46 seconds. The average year is only an integer of 365 days, not a mantissa; A year is divided into 12 months, big month 3 1 day, small month 30 days, and February only has 28 days. The mantissa of four years accumulates to *** 1 day, and is added to February of the fourth year, which is called leap year. So February in leap year has 29 days.
The lunar calendar orders a full moon for one month, ***29 and a half days. For the convenience of calculation, the big moon is customized for 30 days and the small moon is customized for 29 days. In 12 months of a year, large and small months are generally arranged alternately. The lunar calendar has only about 354 days a year, and there is no difference between a normal year and a leap year.
Because the lunar calendar does not consider the movement of the earth around the sun, there is no fixed time for the changes of the four seasons in the lunar calendar, which cannot reflect the seasons. This is a great shortcoming. In order to overcome this shortcoming, people later decided on a compromise calendar, the so-called yin-yang calendar. The summer calendar still in use in China (some people call it lunar calendar or lunar calendar) is this kind of lunar calendar. Like the lunar calendar, it also customizes a month according to the time when the moon is full and short, which is 30 days for the big month and 29 days for the small month. However, it also adopts the method of adding leap months to make the average number of days in each year close to the number of days in the solar calendar to adjust the four seasons. Every two or three years, there will be an extra leap month in the summer calendar.
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