February is packed with interesting observances, but one that stands out is Leap Day—and the Leap Year that makes it possible ...

which is why we have a leap year every four years with 366 days instead of the usual 365. So, leap years help us keep our calendars aligned with Earth's orbit around the sun. Without them ...

We've used leap years for over 2,000 years so our calendars are more in sync with the Earth’s rotation around the Sun. What is a leap year? Generally we define a year as 365 days, but a full ...