Why is an extra day added to February every four years?

It is nice to have the calendar year the same as the Earth's orbit around the Sun. It takes 365 1/4 days to go around the sun...so, each four years, we add a day to correct the calendar.

Thanks Bob!

You're welcome! Adding an extra day to February every four years is known as a "leap year." The reason for this is to keep our calendar year synchronized with the Earth's orbit around the Sun.

Earth takes approximately 365.24 days to complete one revolution around the Sun, not exactly 365 days. To account for the extra 0.24 days each year, we add an additional day to the calendar every four years. This balances out the discrepancy and helps ensure that our calendar remains aligned with the changing seasons.

This practice started with the Julian calendar, introduced by Julius Caesar in 45 BCE. He added one day every four years to account for the fractional value. Later, the Gregorian calendar, which is the one we use today, made some adjustments to further refine the calculation.

By adding a leap day, which falls on the 29th of February, we make the average calendar year length 365.25 days, a closer approximation to the Earth's true orbital period. This helps maintain consistency with the four seasons because without leap years, the calendar would gradually shift over time.

So, the addition of the leap day every four years allows us to keep our calendar aligned with the natural cycles of the Earth's orbit around the Sun.