# How do the days of a date in the Gregorian calendar change through the years?

Each year, the day a date can have goes forward one day, however, on a leap year it goes forward two days; due to the leap years, the days a date can have follows a 28 day cycle:

{Mo, Tu, We, Th}, {Sa, Su, Mo, Tu}, {Th, Fr, Sa, Su}, {Tu, We, Th, Fr}, {Su, Mo, Tu, We}, {Fr, Sa, Su, Mo}, {We, Th, Fr, Sa}

where each block of 4 represent sequential days before a missed day when the leap year occurs. Note that each day appears exactly 4 times, once in each position (each time in a different block) so that each day starts one of the blocks. If the date is after 28 February, the jump occurs in a leap year, but for those before 1 March, the jump occurs in the year after a leap year.

A century is one hundred years long, which means that each year will take 25 blocks from the above cycle to complete: 3 complete cycles plus the first 4 blocks. Numbering the blocks from 0 to 6 in the sequence above:

block 0: {Mo, Tu, We, Th};

block 1: {Sa, Su, Mo, Tu}; ...

block 6: {We, Th, Fr, Sa}

and assuming a date was a Monday in the first year of a leap century, then the blocks used in that century would be:

0123456 0123456 0123456 0123

(If the first day was another day, then the sequence would start from the block which starts with that day, eg if it was a Tuesday, then the block sequence would be: 3456012 3456012 3456012 3456.)

In the Gregorian Calendar a century is only a leap year if the century is divisible by 400. Thus 2000 was a leap year, but 1900 was not. Thus the above cycle of 28 days jumps for 3 out of 4 centuries when the day of the date at the start of the next century follows the day of the last year of the current century.

So carrying on from the above, as the century was a leap year, the next block must start with the day following the last day of the last block, ie the day after the last day of block 3 which is Friday, the block starting with Saturday - block 1; thus the next century would have the block sequence:

1234560 1234560 1234560 1234

Which is one block along from the previous century. So the complete sequence for 4 years starting from a leap century would be:

0123456 0123456 0123456 0123

1234560 1234560 1234560 1234

2345601 2345601 2345601 2345

3456012 3456012 3456012 3456

As the next century would start with a leap year, it starts with the next block in the cyclic sequence, which is block 0 again - the same sequence occurs for every block of 4 centuries starting with a leap century!

From this a complete list of days for every year of any date can be worked out, by changing the start block for the 4 century cycle above.

One this to note is that as the leap day is inserted after 28 February, the years for which the above cycles are appropriate will be slightly different:

For dates after the leap day (ie 1 March and later), the days jump in the leap year itself, so the sequence is appropriate for years starting with the leap century itself, ie the first block relates to the years xx00-xx03, the second to xx04-xx07, etc.

For dates before the leap day (ie 28 February and earlier) the jump occurs the year after the leap year, so the sequence is appropriate for years starting with the year after the leap century, ie the first block relates to the years xx01-xx04, the second to xx05-xx08, etc.

For the leap day itself, that follows the sequence of missing days:

{Tu, Su, Fr, We, Mo, Sa, Th}

Again with jumps on non-leap centuries:

0123456 0123456 0123456 0123

2345601 2345601 2345601 234

3456012 3456012 3456012 345

4560123 4560123 4560123 456

(0 =Tu, 1 = Su, etc).

### Why the change from the Julian to the Gregorian calendar?

The Julian calendar looses a day every 128 years. The Gregorian calendar looses a day every 3200 years.

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### How many days in a year in the time of Jesus?

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### Does the Gregorian calendar have a leap year?

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### When did the Gregorian calendar become standard in its country?

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### When was the New Year's Day on the Gregorian calendar?

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### Was the year 1237 a leap year?

No, odd-numbered years are never leap years in either the Gregorian calendar or the Julian calendar.

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### What describes a major difference between the Jewish calendar and the Gregorian calendar?

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### What is the difference between Julian and gregorian calenders?

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### Is Hanukkah in December?

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In the Gregorian calendar, No Only century years divisible by 400 are leap years.

### What did the Julian calendar have?

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The Gregorian calendar repeats every eleven years not fourteen !

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This is the 299th day of the year (300th in leap years) in the Gregorian calendar.

### How many days in 24 years?

There are 365 days in a year. 365 X 24 = equals 8,760. However, this is not quite accurate when you consider leap years which would have 366 days. At least by the Gregorian calendar. There are 365 days in a year. 365 X 24 = equals 8,760. However, this is not quite accurate when you consider leap years which would have 366 days. At least by the Gregorian calendar. There are 365 days in… Read More

### How many days are in the American calendar?

In the Gregorian Calendar, which is the calendar currently used in every American country, 75.75% of the years have 365 days each, and 24.25% of the years have 366 days each, making the average calendar year 365.2425 days.

### How do the months of the Hebrew calendar correspond to the Gregorian calendar?

Answer 1 The Hebrew months have a rough correspondence to the Gregorian calendar. They line up with Gregorian months in a general way. Answer 2 The Hebrew calendar is a lunisolar calendar which means that there is a general correspondence between the Hebrew months and the seasons, and there is a nearly exact correspondence between the Hebrew dates and the phases of the moon. This is as opposed to the Gregorian calender which is a… Read More

### Why you have leap years in gregorian calendar?

There are about 365.2422 days in an average actual tropical year. Adding an extra day to 97 out of every 400 years makes the average Gregorian calendar year 365.2425 days. So Gregorian has only 97 leap days by adding a day every four years (considering a year has 365.25 days) but then leaving out a leap day in any year 100 that is not 400.

### What is the difference between the Jewish calendar and the Gregorian calendar?

The Jewish calendar consists of twelve lunar months. It also keeps in step with the solar year, by adding a thirteenth lunar leap-month seven times every nineteen years. The Gregorian calendar, which sticks to the solar year, ignores the lunar months and does not attempt to keep in step with them.

### Why does the juilan and the gregorian calendar have leap years?

To compensate for the Earths orbit around the Sun in one year.

### How often does the calendar repeat itself?

The Gregorian calendar repeats in cycles of 400 years, but includes 28-year sub cycles within each century.

### What purpose does a leap year serve?

Every four years the calendar has an additional day in February. The original creators of the Gregorian calendar were not exceptionally good in arithmetic.

### Why did they throw away the old calendar?

We changed from the Julian calendar to the Gregorian calendar because it was out of synch with the solar calendar. The Pope consulted an astronomer and it was decided to add leap years to correct the problems. Catholic countries changed in 1582. However Germany did not until 1700 and Great Britain waited until 1752. Russia did not change until 1918.

### What is a major difference between the Jewish calendar and Gregorian calendar?

The Jewish calendar consists of twelve lunar months. It also keeps in step with the solar year, by adding a thirteenth lunar leap-month seven times every nineteen years. The Gregorian calendar, which sticks to the solar year, ignores the lunar months and does not attempt to keep in step with them.

### What is the difference between Julian and Gregorian calendars?

The fundamental difference between the Julian and Gregorian calendars is this: The Julian calendar year is exactly 365.25 days. The Gregorian calendar year is exactly 365.2425 days. While the difference is small (10.8 minutes), the effect is cumulative. The Julian calendar was adopted in 45 BC. Over the course of the next 1,200 years, the date of the vernal equinox had advanced by ten days. Since the Roman Catholic Church used the equinox to set… Read More

### What calendar did the world adopt in modern history?

The Gregorian calendar, which was promulgated by Pope Gregory XIII beginning in 1582, but was not adopted by some countries until the 18th and 19th century, and not universally applied until the early 20th century. The Gregorian was a correction to the Julian calendar that modified the number of leap years to keep the calendar closer to the astronomical year. The Gregorian year averages 365.2425 days instead of 365.25 days, with the result that 3… Read More

### When was the latest change made in the christian calendar?

The last significant change to the Christian calendar was in 1582, when the Julian calendar was replaced by the Gregorian calendar, which has three fewer leap years in every 400-year period. The leap years that were changed to regular years are the last year of the first three of every four centuries (100, 200, 300, 500, 600, 700, 900, etc.). Although the Gregorian calendar was introduced in the 16th century, it wasn't until the 20th… Read More

### Which person introduced leap years?

Julius Caesar introduced leap years when he reformed the Roman calendar in 46 BCE. His calendar, which is called the Julian calendar, was in use for almost 20 centuries. Beginning in 1582, it was eventually replaced by the Gregorian calendar, which is almost identical to the Julian calendar but is more accurate because it has fewer leap years.

### How does the gregorian calendar differ from the Julian calendar?

The Julian calendar year was exactly 365.25 days. The Gregorian calendar year is 365.2425 days. While the difference is small (10.8 minutes), the effect was cumulative. Over the course of 1,200 years, the date of the vernal equinox had advanced by ten days. Since the Roman Catholic Church used the equinox to set the date of Easter, they considered it undesirable for it to be continually getting earlier in the year, so a change to… Read More

### What is the value of a quarter rupee coin clearly dated 1082 and please tell you why this coin is dated 1082 because this coin was not in circulation until many many years later many thanks?

Not all countries use the Gregorian Calendar. Different states and regions of India have used many different calendars over the years, and for different reasons and purposes. Due to the efforts of the Calendar Reform Committee, India currently use the Gregorian Calendar side by side with the official "Indian National Calendar" or Saka Calendar. Please note that this is little more than a poorly educated guess, but your coin is possibly dated according to the… Read More