2024 is a leap year according to the Gregorian calendar, meaning there will be 1 more day in the year, making a total of 366 days. A leap year only occurs once every 4 years, and only in that leap year will there be an extra day, February 29. In other years, February only has 28 days.
The Gregorian year is calculated by the period of time it takes the Earth to revolve around the Sun. It takes 365 days and 6 hours for the Earth to complete one revolution around the Sun.
The Gregorian year has an integer of 365 days. Thus, a Gregorian year has 6 extra hours and 4 years combined have 24 extra hours, equal to one day.
Therefore, every 4 years there will be a year with 366 days, called a leap year. Leap days in the Gregorian calendar are calculated in February.
Assuming that this difference is not taken into account, each year that passes will increase the distance between the beginning of the Gregorian year and the beginning of a cycle around the Sun by 5 hours, 48 minutes and 56 seconds. If we remove the leap year, then after about 700 years, summer in the Northern Hemisphere will begin in December instead of June. Thanks to the extra day in the leap year, that problem is solved.
Every four years a leap year occurs and has February 29. (Photo: Business Insider)
Why is it 29/2?
We can easily see that if we just take away 2 days from 2 months with 31 days, February will have 30 days and not be too different from other months. However, why do people still keep February with only 28 days and add February 29 in leap years?
This reason comes from the ancient Roman calendar. The Roman calendar was first issued by Romulus, the first emperor of Rome. The calendar he issued was based on the cycle of the Moon, which is similar to the Eastern lunar calendar, but only has 10 months. A year according to this calendar only includes March to December.
The reason was because Romulus thought that this was winter time and had no meaning for farming so there was no need for a convention.
However, around the 8th century BC, emperor Numa Pompilius decided to add 2 more months to the calendar to reach a total of 12 months, each month having 28 days, making the total number of days in a year 354 days.
However, King Pompilius decided to add one more day to January and not change the number of days in February.
From here, the calendar based on the lunar cycle gradually revealed its weakness, it did not properly reflect the seasonal weather cycle, because this cycle was linked to the movement of the Earth around the Sun. And Julius Caesar decided to change the calendar system.
During his time in Egypt, Julius Caesar became convinced of the superiority of the Egyptian solar calendar, which had 365 days and occasionally had a leap month when astronomers observed precise conditions of the stars.
However, instead of always relying on the stars, Julius Caesar realized that he only needed to add one day every four years. To match the Roman tradition of the length of February, that day would fall in the second month of the year - thus the birth of February 29th.
For many centuries after that, the Julian calendar continued to be used normally, but by the mid-16th century, astronomers noticed that the seasons were starting about 10 days earlier than important holidays, such as Easter, which no longer corresponded with seasonal transitions such as spring.
To correct this, Pope Gregory XIII promulgated the Gregorian calendar in 1582. He introduced a calendar that kept the leap day but corrected the inaccuracy by eliminating the leap day in century years that were not divisible by 400 (for example, 1700, 1800, and 1900 were not leap years, but 2000 was).
The introduction of the Gregorian calendar marked the final change to the Western calendar and is used to this day.
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