Computer software programs sometimes do not accept Harold Burkhart’s birth date.

When it happens, the University Distinguished Professor of Forestry at Virginia Tech revises the date to Feb. 28. That is when he celebrates his birthday most years anyway. 

The actual date that he was born — Feb. 29, 1944 — comes around every four years on leap year.

This year he is 19, based on leap year calculations.

“I am still a teenager,” Burkhart said, laughing.

Burkhart is one of the approximately 5 million people globally born on leap day, according to History.com. They are a unique group, referred to as "Leaplings" by some. The odds of being born on a leap day are slim — at 1 in 1,461.

Burkhart remembers his confusion as a 4-year-old when leap year came and his family insisted that he celebrate his birthday on Feb. 29. He had been celebrating on March 1, the day his mom chose for his annual party. Until that point, he assumed March 1 was his birthday.

“This is a difficult concept for a 4-year-old, but by the time I was 8 years old, I got it,” said Burkhart, who grew up in Oklahoma.

Harold Burkhart, a University Distinguished Professor of forestry, was born on Feb. 29, 1944. This year, he will be 19 - in leap years.
Harold Burkhart, a University Distinguished Professor of Forestry, was born on Feb. 29, 1944. This year, he will be 19 - in leap years. Photo by Dan Mirolli for Virginia Tech

He has distinct memories of certain leap year birthday celebrations. For his 16th birthday, his friends and family threw a surprise party for him in the midst of an Oklahoma snowstorm. When he turned 48, Burkhart and his wife threw a party with dinner, dancing, and a bluegrass band at a former Marriott Hotel in Blacksburg. 

This year’s celebration will be more low-key, he said. No big parties are planned.

As an adult, Burkhart decided that he would celebrate his birthday on Feb. 28 on nonleap years. He didn’t like having a March birthday for three years and then having a February birthday.

Even so, he has gotten used to the attention that his unique birth date draws.

“When you are going through security at the airport, occasionally one of those people raise their eyebrows or say ‘Hmm,’” Burkhart said.

Why exactly does Feb. 29 only happen every four years? Joe Wolf, an instructor of medieval history at Virginia Tech, offered some answers about leap day, a common Roman practice that the medieval church made a system in order to keep the date of Easter relatively fixed.

Q: Why does Feb. 29 come only once every four years, generally?

Wolf: Our normal year has 365 days on the calendar, but in reality, the amount of time it takes for the Earth to go around the sun is roughly 365.24 days. So you practically have a quarter of a day that you are accruing in the astronomical time that you’re not accruing on your calendar. You have to reset that quarter of a day every four years. You add an additional day to the calendar every four years, in order to compensate for that quarter of a day you are getting every time the Earth goes around the sun.

Q. Why is having a leap year necessary and why was it created?

Wolf: People have been adding leap days into the calendar for thousands of years. However, the current system dates to the medieval period with the Julian calendar used throughout Europe. It was introduced by Julius Caesar as the reformed calendar of Rome, so when the Christian church became the official religion, they inherited this calendar. But they found the calendar doesn't work as well for calculating the date of Easter, a holiday originally calculated based on Passover, which used the Hebrew lunar calendar.

The big concern is when in the year Easter falls. The medieval church cared about keeping Easter in the spring, calculated based upon astronomical events.

Easter always has to come after the vernal [spring] equinox, following the first full moon. If the date of the vernal equinox was always changing, it made calculating the date of Easter difficult.

Q. What would happen if there was not a leap year, or a leap day, in the calendar?

Wolf: The calendar just continues to march along, adding a quarter day discrepancy every year. The problem is that astronomical events, such as the solstices, equinoxes, and the seasons, will become uncoupled with the months that we associate with them.  

You would get to the point that the vernal equinox was on the 21st of March. Now it’s on the 11th, now it’s in February, now it’s in January, now it’s in December. What that would look like, we could be sitting in the month of July, and it would be winter and snowing outside. That would take a long time to accomplish, about seven centuries without a leap day.

Q: What countries do not have a leap year?

Wolf: Basically every country that has adopted the Gregorian calendar [including the United States] follows leap year. Some countries have additional calendars that also operate in tandem with the Gregorian calendar. Some countries that don’t use the Gregorian calendar are countries like India, Thailand, Bangladesh, but even there they are adding in a leap day to make the conversion easier between their dating scheme and the Western dating scheme.

Most countries, for the sake of international trade, communication and participation in international institutions, such as the United Nations, have some way of accommodating the difference between a local calendar and the Gregorian calendar.

By Jenny Kincaid Boone