Saturday is February 29th, also known as Leap Day. An extra day in the year that many salaried people won’t get paid for.
Okay…the short explanation for why we need leap years is that our calendar needs to stay aligned with the astronomical seasons. The Farmer’s Almanac says it has to do with a full orbit around the Sun which takes about 365.25 days. Our traditional calendar doesn’t account for the extra quarter of a day for the orbit, they just threw in an additional day every four years. This now brings the calendar in line and therefore realigns it with the seasons.
Without leap days, the calendar would be off by 5 hours, 48 minutes, and 45 seconds more each year.
And if you were born on a Leap Day, and you don’t like aging…you only add to your age every four years! So, someone who is technically 50 years old would have had only about 12.5 real birthdays!