As the year 2024 approaches, people around the world are gearing up for a leap year, but not everyone will be welcoming the extra day.

The concept of a leap year arises from the fact that a year in the international solar calendar is not exactly 365 days long. Instead, it consists of 365 days, five hours, 48 minutes and 46 seconds. To account for this extra time, we add an extra day to our calendars every four years. This additional day is what gives us a leap year, complete with the leap day Feb. 29, once every four years.

In the lunar calendar system, traditionally used in many Asian cultures including South Korea, there is the corresponding concept of a leap month, which comes every three years.

Across the world, diverse customs are associated with leap years.

In some Western countries, there is a folk tradition in which women can propose to men during a leap year, particularly on Feb. 29. This tradition originated in Ireland in the fifth century when St. Bridget is said to have complained to St. Patrick about women having to wait too long for marriage proposals due to men’s hesitancy. As a result, women were granted the opportunity to propose, giving rise to what is known as Bachelor’s Day. The tradition was written into law in medieval Scotland.

In Greece and Italy, leap years are considered to bring bad luck to marriage. It is believed that couples who marry during a leap year are more likely to divorce. In Scotland, there is a superstition that people born on a leap day will lead lives filled with untold suffering.

In South Korea, there are no specific customs or traditions associated with a leap year, but some myths related to leap months in the lunar calendar have been carried over, and some people avoid getting married or giving birth on Feb. 29.

At CHA Medical Group, the country’s largest health care group known for its fertility clinics, there’s currently not a single reservation for a cesarean section on Feb. 29 next year, the hospital told The Korea Herald. In 2020, the group also performed no C-sections on the leap day.

“Young parents may not be so concerned, but they often face opposition from their parents who hold more traditional views,” an official from the hospital said.

The chance of a baby being born on Feb. 29 is approximately 0.0684 percent, or 1 in 1,461 days, since the special day only comes around every four years.

Worldwide, there are about 5 million people with leap day birthdays, who are also called “leaplings,” according to BBC News.

Regarding marriage, the tradition of avoiding having a wedding on Feb. 29 has been fading away.

“Recently, leap years have had little impact on couples,” said Kim Chang-kyu, chief of the Korea Wedding Planner Association. “In the past, weddings were centered around family, but now they tend to focus on the couple themselves. They have changed their wedding approaches, sometimes opting to exclude officiants or the pyebaek ceremony.” The pyebaek ceremony is a traditional ritual where the newlyweds pay respect to their families shortly after the wedding.

An official from Westin Josun Seoul said that the hotel has not observed any decline in reservations on Feb. 29, adding that young couples today appear to be “less concerned” about adhering to this tradition.

Yang Sam-yeol, a professor of geomancy at Dongguk University Gyeongju's Graduate School of Buddhist Studies, said some people believe that, as with a leap month in the lunar calendar, there are no ancestral spirits to watch over them on Feb. 29.

The superstition says that no ghost or spirit exists to influence human affairs during leap months, as they do not recognize the month.

“Also, individuals born on the day have difficulty having their fortunes read,” professor Yang said.

For some, a leap day is bad luck for a clear reason. These include soldiers and prisoners.

If a leap day falls within their service period or detention period, they must spend an extra day fulfilling their required military service or serving their sentence.

In 2013, Korea's Constitutional Court said that the duration of a month varies from 28 to 31 days, resulting in differences in the length of sentences depending on the specific time of the year when the sentence is being served. The court also said the occurrence of a leap year is inevitable as long as the solar calendar is in use.

The same principle applies to the military. If Feb. 29 falls within a soldier’s service period, they are required to spend one additional day in the army. This is because the service period is calculated based on months, not individual days.

Similarly, employees who receive a monthly salary receive the same amount regardless of whether they work for 28 days, 29 days or 31 days in a particular month.