A Leap Day, February 29, is added to the calendar during leap years. This extra day makes the year 366 days long – not 365 days, like a common year.
On February 29th, women can ask a man to marry her.
Role reversal on leap day.
When Is the Next Leap Day?
2016 is a leap year, so the next leap day is February 29, 2016.
The last Leap Day was on February 29, 2012.
Why Add a 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 365.242189 days – or 365 days, 5 hours, 48 minutes, and 45 seconds – to circle once around the Sun. This called a tropical year.
Without an extra – or intercalary – day on February 29 nearly every four 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 fixed seasonal days days like the vernal equinox or winter solstice.
Caesar Introduced Leap Years
Roman general Julius Caesar implemented the first leap day in his Julian Calendar, which he introduced in 45 BCE (Before Common Era). A leap day was added every four years. At the time, leap day was February 24, and February was the last month of the year.
Too Many Leap Years
However, adding a leap day every four years was too often and eventually, in 1582, Pope Gregory XIII introduced the Gregorian Calendar. This calendar, which we still use today, has a more precise formula for calculating of leap years, also known as bissextile years.
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Traditions & Folklore
Leap day as a concept has existed for more than 2000 years, and is still associated with age-old customs, folklore and superstition. One of the most well-known traditions is that women propose to their boyfriends, instead of the other way around.
What’s a Leap Second?
The ancient Roman Calendar added an extra month every few years to maintain the correct seasonal changes, similar to the Chinese leap month.