Facts about Leap Year

2012 is a leap year, meaning that February, the shortest month, has an extra day, bringing the year to 366 days. This notable event comes only every four years. Which means you have an extra 24 hours. So what will you do with yourself? 

Lookups on the Web are taking a leap, including "leap day activities," along with the quadrennial questions: "what is leap year," "why is there a leap year" and "history of leap year." Here, your guide to the day.

When is it? An extra day is added to the month of February every four years. This year, Leap Day is on Wednesday, February 29.

Why we need Leap Day: Usually, our year is 365 days long. Except that it's not: A full cycle of seasons is actually 365 days, 5 hours, 49 minutes, and 16 seconds long, or about 365.25 days. Over time, the extra quarter of a day adds up, and without Leap Day, the calendar would be one day out of sync with the seasons. After 30 years, it would be about a week off, and after 100 years, it would be nearly a month off.

Bing Quock, the assistant director of Morrison Planetarium at the California Academy of Sciences, explains, "Leap Day is added as a correction to the calendar so that it stays in sync with the seasons ... that way, the seasons start on the same day from year to year to year."

The history of Leap Year: Leap Year has been around for 2,000 years, since Julius Caesar created the 365-day calendar, although Caesar's astronomer, Sosigenes, get s credit for adding an extra day in February every four years.