Leap Day: February 29

A Leap Day, February 29, is added to the calendar in Leap Years. This extra (intercalary) day makes the year 366 days long – and not 365 days, like a common (normal) year. Leap Years occur nearly every 4 years in our modern Gregorian Calendar.

When is the next Leap Year?

2016 is a Leap Year, so the next Leap Day falls on February 29, 2016.

The last Leap Day was on February 29, 2012.

What years are Leap Years?

Traditions and folklore

Leap Day as a concept has existed for more than 2000 years, and is still associated with age-old traditions, folklore and superstition. One of the most popular traditions is that women propose to their boyfriends.

Leap Day Traditions and Superstitions

Leap Day Trivia

Brief history of the Leap Day

Leap Days are needed to keep our calendar in alignment with the Earth's revolutions around the Sun. It takes the Earth approximately 365.242199 days (a tropical year) to circle once around the Sun. If we didn't add a day on February 29 nearly every 4 years, we would lose almost six hours every year. After only 100 years, our calendar would be off by approximately 24 days in relation to the seasons.

The ancient Roman Calendar added an extra month every few years to maintain the correct seasonal changes. Julius Caesar implemented a new calendar – the Julian Calendar – in 45 BCE (Before Common Era) with an extra day added every 4 years. At the time, Leap Day was February 24, and February was the last month of the year.

What's a Leap Second?

February 30 was a real date

Too many Leap Years

In 1582 Pope Gregory XIII refined the Julian calendar with a new rule that a century year is not a Leap Year unless it is evenly divisible by 400. This transition to the Gregorian Calendar was observed in some countries including Italy, Poland, Portugal, and Spain. The transition took longer for other countries; Great Britain started using the Gregorian Calendar in 1752 and Lithuania in 1915.

Why are some days missing in the 1752 U.S. calendar?

Leap Year in other calendars

• Chinese Leap Year
• Jewish Leap Year
• Leap Year in Iran
• Leap Year in Islam
• Bahá'í Leap Year
• Hindu Leap Year
• Ethiopian Leap Year

Topics: Leap Year, Calendar, February