When does the decade end?

[Chadwick]

When a baby is born they are aged 0, celebrating their 1st birrthday a year later. So if the calendar is assumed to relate to when it was originally thought Christ was born then he was born in year 0, with year 1AD (one year after Christ's birth), being his 1st birthday. Thus, meaning a decade runs from the first day in year 0 to the last day in year 9, and every subsequent decade staring on the first day in a year ending in 0 and ending ot the last day in a year ending in a 9.

Therefore, the decade ended yesterday on 31 December 2019. And a new decade starts today - 01 January 2020. HAPPY NEW YEAR.

It's a great explanation except for one fatal flaw: there is no year 0.

[Chadwick]

It is not when Jesus was born but when we started Anno Domini which was year one so for me, and many others, the decade ends on 31st December 2020. For others it ended on 31st December 2019. The only thing for sure is nothing really changed at midnight last night other than the date.

I think you're trying to hold back the tide.

There is an argument that a) 'decade' means 10 years, and b) if you phrase it as 'the 220th decade AD', then c) the decade must change at the end of 2020. But 'decade' has another more common definition.

The concept of a decade is generally understood as the 10 years sharing the same 'tens' digit in the year. eg. The nineteen fifties, the 60s, the 80s etc. Running from eg. 1980 to 1989 inclusive. It doesn't matter how many years have elapsed since we arbitrarily declared year 1.

[kevinchess1]

When a baby is born they are aged 0, celebrating their 1st birrthday a year later. So if the calendar is assumed to relate to when it was originally thought Christ was born then he was born in year 0, with year 1AD (one year after Christ's birth), being his 1st birthday. Thus, meaning a decade runs from the first day in year 0 to the last day in year 9, and every subsequent decade staring on the first day in a year ending in 0 and ending ot the last day in a year ending in a 9.

Therefore, the decade ended yesterday on 31 December 2019. And a new decade starts today - 01 January 2020. HAPPY NEW YEAR.

It's a great explanation except for one fatal flaw: there is no year 0.

It's also not thought though
IF one year is at the end of year one, then 10 years are at the end, not the beginning of the 1oth year.

[kevinchess1]

It's a great explanation except for one fatal flaw: there is no year 0.

In primary school, I was a bit mouthy(Hard to believe I know)
'Sir, is it right that before Jesus, the years were BC?'
'Yes that's correct Chessy.'
'And afterwards the years are AD?'
'Yes that's right'
'Sir then how come Boxing Day isn't New Years day then?'

He told me to Shut up.

[blythburgh]

It's a great explanation except for one fatal flaw: there is no year 0.

In primary school, I was a bit mouthy(Hard to believe I know)
'Sir, is it right that before Jesus, the years were BC?'
'Yes that's correct Chessy.'
'And afterwards the years are AD?'
'Yes that's right'
'Sir then how come Boxing Day isn't New Years day then?'

He told me to Shut up.

We could open another pandora's box on when New Year's Day should be. The Celts thought it was 1st November so should the Scot's change the date of Hogmanay? It used to be on 25th March for early Medieval Brits. Then there is the New Year date of other religions and do not forget the Chinese New Year.

Should we celebrate them all and have lots more New Year's Eve parties?

[BeautifulSunshine]

It's a great explanation except for one fatal flaw: there is no year 0.

In primary school, I was a bit mouthy(Hard to believe I know)
'Sir, is it right that before Jesus, the years were BC?'
'Yes that's correct Chessy.'
'And afterwards the years are AD?'
'Yes that's right'
'Sir then how come Boxing Day isn't New Years day then?'

He told me to Shut up.

We could open another pandora's box on when New Year's Day should be. The Celts thought it was 1st November so should the Scot's change the date of Hogmanay? It used to be on 25th March for early Medieval Brits. Then there is the New Year date of other religions and do not forget the Chinese New Year.

Should we celebrate them all and have lots more New Year's Eve parties?

Yes, lots more New Year's Eve parties.