Why do we have leap years?
LEAP YEAR IS THE YEAR IN EVERY FOUR THAT HAS 366 DAYS INSTEAD OF 365. THE EXTRA DAY IS ADDED TO FEBRUAY TO MAKE THE CALENDAR YEAR NEARLY THE SAME AS THE SOLAR YEAR.
Leap year has 365 days, one more day than an ordinary year. The calendar we use is based on the amount of time it takes the earth to make one revolution around the sun. this takes about 365 ¼ days.
For convenience, we ignore the extra one-fourth-day for three years in every four. After four years, the leftover time adds up to one full day.
We add this extra day to the calendar, and say that it has 365 days. This fourth year is called “leap year”, and the extra day is February 29.
But the year is not exactly equal to 365 ¼, days either. It is actually about 11 minutes shorter. Adding an extra day in leap year makes the average calendar a few minutes too long.
So, the day is not added in the century years, except those that can be divided by 400. Thus A.D. 2000 will be a leap year, but 2100 will not, nor was 1900.
A person born on February 29 can choose his own birthday – either February 28 or March 1. – Dick Rogers