20 16 * * How many days are there?

Because 20 16 is a leap year, on February 29th, 20 16 16 is divisible by 4, so it is a leap year.

There are 7 big months and 4 small months in the solar calendar every year, 1 flat month or leap month, that is, February, with 28 days in a normal year and 29 days in a leap year.

A leap year is a leap year in the solar calendar, a leap year in the lunar calendar is called a leap month, a leap year in the solar calendar is 366 days, and a leap month in the lunar calendar is 13 months.

20 16 65438+ 10, March, May, July, August, 65438+ 10 and 65438+February are big months, with 3 1 day per month. April, June, September, June and116 are abortion, with 30 days per month. 20 16 February is 29 days.

The total number of days of 20 16 is: 3 1×7+30×4+29=366 (days).

Extended data:

A year with a leap day in the solar or lunar calendar, or a year with a leap month in the yin and yang calendar. Leap year is once every four years, or one year in every four years is a leap year. Leap year discipline: astronomy (first-class discipline); Astrometry (two disciplines). The establishment of leap year is to make up for the time difference between the number of days in a year and the actual period of revolution of the earth caused by man-made calendar regulations. The year to make up for the time difference is leap year.

The leap year in the solar calendar * * * has 366 days (1-kloc-0/day, 29 days, 3 1 day, 30 days, 3 1 day, respectively in February).

Because the earth's revolution is 365 days (or 365.25 days) 5: 48: 46, which is 5: 48: 46 different from a year. This will increase by one day every four years. Therefore, a non-century year divisible by four is a leap year, but there is one more day every 400 years. Therefore, it was later stipulated that only century years divisible by 400 were leap years.

Leap year in the solar calendar:

The period of the earth's orbit around the sun is 365 days, 5 hours, 48 minutes and 46 seconds (365.438+09 days), which is the tropic of cancer. The Gregorian calendar has an average of only 365 days a year, which is about 0.2422 days shorter than the tropical year, and the remaining time is about four years. So February 4th is added with 1 day, making the calendar year of that year 366 days, and this year is a leap year. The current Gregorian calendar has 97 leap years every 400 years.

According to a leap year every four years, the average annual calculation will be 0.0078 days, and it will increase by about 3 days after 400 years. So every 400 years, there will be three leap years. Therefore, it is stipulated that the Gregorian calendar year is a whole hundred, and it must be a multiple of 400 to be considered as a leap year, not a multiple of 400. Although it is a multiple of 4, it is also a normal year. This is what is usually said: leap in four years, leap in a hundred years, and leap in four hundred years. For example, 2000 is a leap year, and 1900 is a normal year.

Lunar leap year:

The calendar month of the lunar calendar (that is, the lunar calendar in China) is based on the new moon. The time of the first lunar month is 29th 12 hours, 44 minutes and 3 seconds (i.e. 29.5366 days), so the first lunar month is 30 days and the second lunar month is 29 days. The lunar calendar basically takes1February as a year, but the time of 12 lunar month is 354.3667 days, which is about 1 1 day different from the tropical year. This will add 33 days every three years, that is, about one month.

In order to eliminate the extra days, one month is added every three years, which is the leap month of the lunar calendar. A year with a leap month is also called a leap year, so there is a folk saying that three years are two leaps and three years are not leap. Therefore, the lunar leap year has 13 months. As for the leap month, it is determined by the solar terms.

The general rules for judging leap years in Gregorian calendar are: leap once every four years, not leap for a hundred years, and leap again every four hundred years.

For example, 1996, 2000, 2004, 2008, 20 12 is a leap year, 2000, 3000, 4000 is a leap year, and 2 100, 2200, 2300 and 2500 is a leap year.

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