Happy New Year and welcome to 2020. You may have heard some arguing whether it is the start of a new decade or it is not. Here is the simple answer.
TECHNICALLY it is not. The system of our year numbering, though imposed retroactively, in a flawed manner and adjusted several times, there was no year zero. We went straight from 1 B.C. to 1 A.D. Therefore the first decade was year 1 to year 10, the second decade ran year 11 to 20, 21 to 30 and so on. So in this reckoning the new decade will start on 2021.
POPULARLY it is. And you can’t blame people. When you describe what you did in the ’20s you include every year that starts with a 20, right? In this reckoning, the decade runs from 2020 to 2029. Makes sense unless you are strict mathematician or historian.
And of course if you are Chinese or Jewish you have an entirely different calendar and New Year’s Day. But I digress and that will only get us even more confused (focus, people, focus).
As long as you understand the above, who cares? It is one of the least consequential questions you will face this year. Relax and enjoy the new year. And the new decade if that is how you want it. Happy New Year.