LEAP YEAR AND LEAP DAY

In the Gregorian calendar(used by most countries), Leap Day is the extra day in Leap Year that occurs every 4 years. The next leap year is February 29, 2012. Leap years are every year that is divisible by 4, except years that are divisible by 100, unless the year is also divisible by 400. Sound confusing? Then all you need to know is that leap year is every 4 years skipping the years 2100, 2200, 2300, 2500, etc.

Leap years are required so that the calendar stays in alignment with the earth's motion around the sun. This alignment, calculated by the mean time between two successive vernal equinoxes, is 365.2422 days long, resulting in an error of .2422 days in a 365 day calendar year. After 100 years, the calendar would be more than 24 days ahead of the seasons. Leap years keep the calendar in line with the seasons.

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