Why do we need leap year?
The length of the solar year, however, is slightly less than 365¼ days—by about 11 minutes. To compensate for this discrepancy, the leap year is omitted three times every four hundred years.
In other words, a century year cannot be a leap year unless it is divisible by 400. Thus 1700, 1800, and 1900 were not leap years, but 1600, 2000, and 2400 are leap years.
There is a Greek superstition that claims couples have bad luck if they marry during a leap year.