On February 29th 2020 many cover collectors celebrated this event by sending out many covers on exact day, by some of them did more and designed commemorative covers, like this one, designed ans sent by my friend Trevor Ashman. A leap year is a calendar year that contains an additional day 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 the same number of days in each year drift over time with respect to the event that the year is supposed to track. By inserting an additional day or month into the year, the drift can be corrected.
Thank you, Trevor!