Every four years most of the world gets an extra day to do whatever it is they do on most days.

This year is a Leap Year and our calendar has 366 days. The extra day creates Feb. 29, a date not usually seen on calendars.

The extra is added to keep the calendar year synchronized with the astronomical year or seasonal year. Because astronomical events and seasons do not repeat in a whole number of days, calendars that have a constant number of days in each year will inevitably drift over time with respect to the event that the year is supposed to track, such as seasons. 

If the extra day wasn’t added, over a period of about 700 years our summers could start to occur in December.

According to the Smithsonian National Air and Space Museum, the name “Leap Year” has less to do with an extra day during those years and more when our birthdays and other holidays happen.

If your birthday were to occur on a Monday one year, the next year it should occur on a Tuesday. However, the addition of an extra day during a leap year means that your birthday now “leaps” over a day.

Instead of your birthday occurring on a Tuesday as it would following a common year, during a leap year, your birthday “leaps” over Tuesday and will now occur on a Wednesday.

Folks who are born on Feb. 29, get their choice of when to celebrate their birthday on non-Leap Years, usually either Feb. 28 or March 1. 

Businesses use the extra day as a marketing tool, often offering sales and discounts, especially for those who can prove they were born on Feb. 29.