What Is a Leap Year?

Learn How Leap Years Keep Our Calendar Accurate

December 30, 2020
29 Leap Year Fence

Leap years keep our calendars in check! Allow us to explain why leap years are necessary and share some of the fun folklore surrounding them. 

What Is a Leap Year?

Simply put, a leap year is a year with an extra day—February 29—which is added nearly every four years to the calendar year.

Why Are Leap Years Necessary?

Adding an extra day every four years keeps our calendar aligned correctly with the astronomical seasons, since a year according to the Gregorian calendar (365 days) and a year according to Earth’s orbit around the Sun (approximately 365.25 days) are not the exact same length of time. Without this extra day, our calendar and the seasons would gradually get out of sync. (Keep reading for a longer explanation.) 

Because of this extra day, a leap year has 366 days instead of 365. Additionally, a leap year does not end and begin on the same day of the week, as a non–leap year does.

How Do You Know If It’s a Leap Year?

Generally, a leap year happens every four years, which, thankfully, is a fairly simple pattern to remember. However, there is a little more to it than that.

Here are the rules of leap years:

  1. A year may be a leap year if it is evenly divisible by 4.
  2. Years that are divisible by 100 (century years such as 1900 or 2000) cannot be leap years unless they are also divisible by 400. (For this reason, the years 1700, 1800, and 1900 were not leap years, but the years 1600 and 2000 were.)

If a year satisfies both the rules above, then it is a leap year. 

When Is the Next Leap Year?

Leap Year Leap Day
2024 Thursday, February 29
2028 Tuesday, February 29
2032 Sunday, February 29
2036 Friday, February 29

Why Do We Need Leap Years?

The short explanation for why we need leap years is that our calendar needs to stay aligned with the astronomical seasons.

One orbit of Earth around the Sun takes approximately 365.25 days—a little more than our Gregorian calendar’s nice, round number of 365. Because the calendar does not account for the extra quarter of a day that the Earth requires to complete its orbit around the Sun, it doesn’t completely align with the solar year. 

Because of this .25 difference, our calendar gradually gets out of sync with the seasons. Adding an extra day, aka a “leap day,” to the calendar every 4 years brings the calendar in line and therefore realigns it with the seasons.

Without leap days, the calendar would be off by 5 hours, 48 minutes, and 45 seconds more each year.

After 100 years, the seasons would be off by 25 days! Eventually, the months we call February and March would feel like summer months in the Northern Hemisphere.

The extra leap day adjusts this drift, but it’s not a perfect match: Adding a leap day every four years overcompensates by a few extra seconds each leap year, adding up to about three extra days every 10,000 years. 

What Is a Leap Day? And a Leapling?

A “leap day” is the extra day in the leap year: February 29.

A “leapling” is a person born on a leap day. Any leap day babies out there? We’d love to hear from you in the comments below!

Leap Year Facts and Folklore

  • Ages ago, Leap Day was known as “Ladies Day” or “Ladies’ Privilege,” as it was the one day when women were free to propose to men. Today, Sadie Hawkins Day sometimes applies to Feb 29 (leap day), based on this older tradition.
  • According to folklore, in a leap year, the weather always changes on Friday.
  • “Leap year was ne’er a good sheep year” (old proverb)

Are Leap Years Bad Luck?

Many feel that to be born on Leap Day, thereby becoming a “leapling,” is a sign of good luck.

In some cultures, it is considered bad luck to get married during a leap year.

We don’t know of any evidence supporting that marriage theory, but we do know that during leap years:

  • Rome burned (64),
  • and the Titanic sank (1912).

By the same token, also in leap years:

  • the Pilgrims landed at Plymouth, Massachusetts (1620),
  • Benjamin Franklin proved that lightning is electricity (1752),
  • and gold was discovered in California (1848).

Do you have any leap year memories? Are you a Leapling yourself? Please share in the comments below!


The Old Farmer's Almanac



Reader Comments

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Leap Day Baby

I am a Leap Day Baby, born 02/29/1964. I recall my mother telling me that she was so concerned when she went in labor. She thought it was her fault & that I would be mad at her for only having a birthday every 4 years. I was never mad, in fact, quite the opposite. I always felt like I was special compared to my sisters & in-life. For example, I was the only blonde in a family of brunettes/dark hair, pictures you will notice the big smile I had, I was naturally athletic, & was often told by other people that I had an attractive glow/aura about me. Being a Leap Day Baby to me just confirmed how unique I am.

As far as celebrating my birthday during non-Leap Day Years, I celebrate on both February 28th & March 1st. Why? It's only logical, really. When there is a February 29th it is the last day of the month, thus February 28th on non-Leap Day Years. However, February 29th falls where March 1st would be on non-Leap Day Years. So, I celebrate my birthday 2 days on non-Leap Day Years, but I refer to my real birthday of Leap Day as my "big deal" birthday.

Thanks for the opportunity to share my thoughts.

Leap Year Baby at 16/66

I prefer the term Leap Year Baby to leapling. Leap Year Baby is what I grew up with and is more common. I do not care for the term "leapling" at all. I am 16 in Leap Years until next year, 2020, which is Leap Year. Some Leap Day Babies call their non-Leap Day birthdays (3 out of 4 years) their "Un-Birthday." I always celebrate on February 28 - I tell everyone that my birthday is the last day of February - no matter what year it is!

I wish calendars always listed Leap Day on February 29th, but most don't acknowledge it, yet they list Ground Hog Day on Feb. 2! Both are based on the astronomical calendar system we use. (Ground Hog Day is half way through winter, which is based on solstices and equinoxes.) Do Farmer's Almanac calendars show Leap Day on Feb. 29?

There are several Facebook groups you can join if you or your child were born on Feb. 29: Honor Society of Leap Year Day Babies, and Leap Year Babies are a couple of them. It's fun to connect with people all over the world who share the same unusual birthday and run into the same problems and satirical comments. Like trying to open an account online where the system that requires you to add your birthday does not know to include February 29 as a choice! It's Twenty Nineteen, folks, and still not every company or city/county government office has figured out that someone can actually be born on Leap Day! Happy Un-Birthday this Feb. 28 to all of you out there who share my birthday!

Leap Day

The Editors's picture

To answer your question regarding Old Farmer’s Almanac Calendars: We do indeed label February 29 as Leap Day. Keep an eye on our online store for our 2020 calendars! 

Thank you!

I will let some of the Leap Day Baby sites know that Farmer's Almanac supports labeling Leap Day when it's Leap Year!

I'm a leap year baby. Only 16

I'm a leap year baby. Only 16 birthdays in my life. Only problem is...have to multiply times 4. (LOL) I have fun with it because people don't know which day to call me...so I tell them either is fine . In 2016 a restaurant I went to wrote "Happy 16th Leap Year Birthday" they wrotevit with icing on a plate..it was pretty cool!


To all those leaplings can I ask is do you only celebrate your birthday every 4 years or do you celebrate on Feb 28 or March 1 ?

Leap Year

I was born 2-29-1948. I am 17 in birthdays. I have always liked being born on leap day. My kids always loved it when they became older than me in birthdays. My youngest, when she became older than me, she went to school telling her teacher that she was now older than her mother. They asked her how could that be. So she explained

Leap Year

Leapling born 02-29-1964
It's easier now I'm older and don't care so much about birthdays! It's kind of fun having to only celebrate once every four years.

Leap year

I had identical twin girls on leap year 2/29/1988 it was 52 year between my twins and my twin Great aunts my twins are name after them

Leap year


Leap Day puppy

I have a miniature pincher pup. He was born leap day 2012. He is without a doubt the most mischievous dog I have ever had. It's like every thing he does, he is out to prove he is special. His mother and father are both red minis, he is a perfectly marked black. He jumps higher than seems possible, as long as his target is something to eat that he shouldn't have. No matter, I love him to pieces.

My birthday

Last year was my birthday (02/29/2016) and I was turning 12 years old, people in my class kept asking me how my birthday works. I explained it in the most simple way I can, by saying that an extra day is added in February, every 4 years passing, and for some reason, they are still confused by when I say that. And whenever something involving our ages is involved, they always have the nerve to make fun of my birthday by saying that I'm 3. Sometimes having a birthday on a leap year is a blessing and a curse. But at least I have the rarest birthday in the world. :)

Leap year

I was born in July, 2004. So am I really 3 years old?


2/29/84 on the off yrs when does everyone celebrate?

Leap year babies rule

I am a leap year baby born on 2,000 I am suppose to be sixteen but Since i am a leap year baby I am 4 years old

Leap Year Baby

The Editors's picture

Hi leapling, Happy sweet 16! And how fun to think you’re four-years-old.  Maybe have a party and include some four-year-old fun like blowing bubbles! :-)

No, honey

You're a leapling, not a Leap Year Baby.

Neil Armstrong and Buzz

Neil Armstrong and Buzz Aldrin landed on the moon on July 20, 1969, that was a giant leap year.

...but not a real leap year.

...but not a real leap year.

My son was born 2/29/88 what

My son was born 2/29/88 what a beautiful day that was he's 7 in leap years but today he turn 28yrs old

leap dày

My first grand daughter was born on leap day 2012! She such a blessing and so smart.

A Great Marriage!

We were married on February 29, 2004. The minister who married us asked my husband how often we would celebrate our anniversary since it was on Leap Day...every four years? No, my husband responded. We will celebrate EVERYDAY... and we have. Looking forward to year 12 next Monday (or is that three ???)


Marriage on Feb 29 2016 3:30 in Santa Ana, California Court House
MAILE Pisces Monkey "(Laos)"
GEORGE Pisces Serpent "(Mex/Amer)"

I proposed to my husband and

I proposed to my husband and we were married on Feb 29,08 at 7:49pm. (We only celebrate our anniversary on the actual day.) Our 1st anniversary we our daughter decided she wanted to grace us on Feb 29, 2012 at 8:07am 2months premature. Our little leapling will celebrate her "1st" 4th birthday this year!!

leap year babies

I was born on the 29 and so was my younger brother

Leap Year

I was born Feb. 29, 1972.. I will be 44 this year and 11 in leap years..

Me too nice to meet you

Me too nice to meet you

I'm a leap year baby. I was

I'm a leap year baby. I was born Feb. 29,1964.

Leap year

These are great facts to know

Is it time to make a change?

Is it time to make a change? One would think it should be time for any other calendar change. Why, well think it seems as though we are are a month behind the physical seasons change. When august began at times the temp dropped and everyone said well say good bye to summer. That used to take place in September.