February 29 is a date that usually

**occurs every four years**, and is called**leap day**. This**day**is added to the calendar in**leap years**as a corrective measure, because the Earth**does**not orbit the sun in precisely 365 days. The Gregorian calendar is a modification of the Julian calendar first used by the Romans.In this way, how often does leap year come around?

Learn what a leap year is, why we have leap years, and how often we have a leap year. The Earth orbits the sun every

**365.2422**days (0.2422 days is equal to 5 hours, 48 minutes and 46 seconds, roughly 1/4 of a day). Every 365 1/4 days (not exactly 365 days), the Earth returns to the same exact spot in its orbit.Why every 100th year is not a leap year?

A

**year**is a**leap year**if it is divisible by 4, but century**years**are**not leap years**unless they are divisible by 400. So, the**years**1700, 1800, and 1900 were**not leap years**, but the**year**2000 was, which is why in a given**100 years**, there are 24**leap years**and 76 ordinary**years**.