Since 2019 ends in a '9', it begs the question, when does a decade really begin?

Will this decade end on December 31, 2019, and the new decade begins January 1, 2020?  Or will the new decade technically start a year later on January 1, 2021?

The Farmers’ Almanac says for a decade to begin, it must start with the year ending in '1' and finish with a '0'.

By that logic, this current decade started on January 1, 2011, and will end on December 31, 2020.

Remember all the wild celebrations on December 31, 1999.  It seems that we were celebrating a year too soon!

According to the Farmers' Almanac, the 21st century opened and the start of the new millennium began on January 1, 2001.

Think of it this way.  Go into a building where the ground floor is listed not as the first floor, but as the lobby.  So the first floor is actually one flight above you.

If you took the elevator from the lobby 10-flights up, you would actually end up on the ninth floor, if you assume that the lobby as the “zero” floor.

Now assume the lobby as the “first floor" and go 10-flights up, you would end up on the tenth floor.

The Farmers' Almanac surmises that January 1, 2011, was the equivalent of a “first-floor lobby,” and after going up to ten flights (or years), we’ll arrive at the tenth floor.  Or in this case, December 31, 2020, when this decade ends.

Source: Farmers' Almanac