The Julian calendar has two types of years: a normal year of 365 days and a leap year of 366 days. They follow a simple cycle of three normal years and one leap year, giving an average year that is ...

So, 2000 was a leap year. To find the day of year number for a standard date, scan down the Jan column to find the day of month, then scan across to the appropriate month column and read the day of ...

The Julian calendar included leap years every four years without exception and was synced up to Earth's seasons thanks to the "final year of confusion" in 46 B.C., which included 15 months ...

But who invented it, where did it come from, and what makes a leap year? Here are six facts about why the Gregorian Calendar. Before Pope Gregory XIII instituted the Gregorian calendar in October 1582 ...