Hannah OrtegaAustin American-Statesman
Show Caption
The month of February is getting an extra day in 2024.
This phenomenon is known as a leap year, with the additional 29th day of February acting as leap day. Leap years come along every four years, but why exactly do they happen?
Here's what you need to know:
Why do we have leap years?
While there are 365 days in a year, it actually takes the Earth 365 ¼ days to orbit fully around the sun. Without leap years, "seasons would be thrown off, as our equinoxes and summer and winter solstice would no longer align with the seasons," according to USA TODAY.
The off-balance seasons and days would happen gradually, just as they did centuries ago. According to TIME, Europeans of 1582 experienced a 10-day discrepancy thanks to a slightly off calendar from Julius Caesar, which led to an extra 11 minutes per year over the course of thousands of years.
When did leap years start?
According to TIME, the origin of Leap Years can be traced back to 46 BCE and 1582 as well as two historical figures: Julius Caesar and Pope Gregory XIII, respectively.
Caesar created a new Julian calendar for Rome that measured a year as 365.25 days long, as the original Roman year was 10 days shorter than a modern year. The seasons were thrown off as a result of this short original calendar.
More: Earth gained 75 million humans in 2023. The US population grew at half the global rate
However, Caesar's calendar "was 11 minutes and 14 seconds too long—and Europeans kept using it for the next thousand-plus years," according to TIME. This led to the aforementioned 10-day discrepancy in 1582.
That's when Pope Gregory stepped in with a Papal Bull that put Oct. 15 directly after Oct. 4. He also declared that "every four years would be a leap year, unless it was the beginning of a new century —except for every 400 years, when wewouldkeep the extra day," according to TIME.
When is leap day?
Leap day is on Thursday, Feb. 29, 2024
How old are leap day babies?
Here's a list of how birthdays and ages shake out with leap years:
- 1916:You'd be 108 years old or 27.
- 1920:You'd be 104 years old or 26.
- 1924:You'd be 100 years old or 25.
- 1928:You'd be 96 years old or 24.
- 1932:You'd be 92 years old or 23.
- 1936:You'd be 88 years old or 22.
- 1940:You'd be 84 years old or 21.
- 1944:You'd be 80years old or 20.
- 1948:You'd be 76 years old or 19.
- 1952:You'd be 72 years old or 18.
- 1956:You'd be 68 years old or 17.
- 1960:You'd be 64 years old or 16.
- 1964:You'd be 60 years old or 15.
- 1968:You'd be 56 years old or 14.
- 1972:You'd be 52 years old or 13.
- 1976:You'd be 48 years old or 12.
- 1980:You'd be 44 years old or 11.
- 1984:You'd be 40 years old or 10.
- 1988:You'd be 36 years old or 9.
- 1992:You'd be 32 years old or 8.
- 1996:You'd be 28 years old or 7.
- 2000:You'd be 24 years old or 6.
- 2004:You'd be 20 years old or 5.
- 2008:You'd be 16 years old or 4.
- 2012:You'd be 12 years old or 3.
- 2016:You'd be 8 years old or 2.
- 2020: You'd be 4 years old or 1.
If you're born in a leap year, when can you legally drink, vote, or drive?
Legality in terms of drinking and voting is not impacted by leap years, even if someone is "technically" not 18 or 21. If you're born on February 29, your birthday would be observed after 11:59 p.m. on Feb. 28 — or March 1 — on non-leap years.
What else should I know about leap years?
A year is only a leap year if it is evenly divisible by four, and "if the year can be evenly divided by 100, it is not a leap year unlessthe year is also evenly divisible by 400," according to USA TODAY.
