Why every fourth year is not a leap year
What's the story
As we ring in 2024, we also welcome an extra day, making this year a leap year. This additional day, called "leap day," is added to February, extending it to 29 days instead of 28.
Leap years happen every four years, with the previous one in 2020 and the next in 2028.
The main reason for this extra day is to keep our calendar in sync with Earth's orbit around the Sun and maintain consistency in our seasons.
Details
The significance of leap day
Our planet takes about 365.2422 days to complete its orbit, which is slightly longer than the standard calendar year of 365 days.
While this disparity might not seem like much, over time it can lead to considerable differences in the calendar. For this reason, February, which is typically the shortest month of the year gets an extra day every four years.
Without leap years, the calendar would gradually become out of sync with the seasons.
What Next?
Not every fourth year is a leap year
For a year to be considered a leap year, it must meet specific criteria. The primary requirement is that the year should be divisible by four. If the year is divisible by 100, it's not a leap year unless it is also divisible by 400.
After 1896, 1900 was not a leap year because although it's divisible by four and 100, it wasn't divisible by 400.
This rule ensures that the calendar remains aligned and accurate with the astronomical year.
Insights
History behind leap day
The practice of adding a leap day goes back to Julius Caesar's calendar reforms in 46 BC. The Roman calendar, which was shorter than the solar year had 355 days, causing it to be out of sync with the seasons eventually.
Caesar introduced the Julian calendar, based on the solar calendar, which included a leap-year system.
Later, in 1582, when the Julian calendar was refined into the modern Gregorian calendar, the practice of adding a leap day continued.
Facts
Fun facts and traditions associated with leap day
There are many traditions and superstitions around leap day.
In Greece, it is considered unlucky to get married on a leap day, and one in five engaged couples intends to forego getting married during a leap year.
Meanwhile, in Ireland, this day is known as Bachelor's Day as on this day women propose to men. If the proposal is refused, the man is expected to buy the lady in question an expensive dress or coat.