diamond geezer

Sunday, March 31, 2024

You've probably noticed that Easter Day moves around a lot. Yes, it can fall on any date between 22nd March and 25th April, but it never seems to end up on the same weekend it did last year. And indeed it never can.

This year Easter is quite early, being Sunday 31st March. The matching Sunday next year would be 30th March but Easter Day won't be that, it's jumping ahead three weekends to land on Sunday 20th April.

Let's take a look at how the date jumps around during the 2020s. See how the date never appears in the same column two years running.

 Date of Easter Day 25-31 Mar 1-7 Apr 8-14 Apr 15-21 Apr gap 2020 12 April 2021 4 April 357 days 2022 17 April 378 days 2023 9 April 357 days 2024 31 March 357 days 2025 20 April 385 days 2026 5 April 350 days 2027 28 March 357 days 2028 16 April 385 days 2029 1 April 350 days 2030 21 April 385 days

The gap between Easters is never 364 days, only ever 350 days, 357 days, 378 days or 385 days.

In other words Easters are only ever 50, 51, 54 or 55 weeks apart, never 52 or 53.

Let's look at that last column more closely.
Here's a graph which shows the gaps between Easters for the first quarter of the 21st century.

See how the number of days jumps around, always missing 364 days and 371 days. There seems to be no obvious repeating pattern, but 2022 stands out as a bit of an oddity.

In particular some of the gaps seem to occur more frequently than others. So I checked the date of Easter for the whole of the 20th and 21st centuries, that's 200 gaps, and these are the results I found.

If you prefer that as a table...

 Gaps between Easters 350 days 50 weeks 23% 357 days 51 weeks 41% 378 days 54 weeks 7% 385 days 55 weeks 30%

A 51 week gap is most common, i.e. Easter is a week earlier than last year. That's what's happened in 2024.
A 55 week gap occurs about a third of the time, i.e Easter is three weeks later than last year.
A 50 week gap occurs about a quarter of the time, i.e Easter is two weeks earlier than last year.
A 54 week gap only occurs about once every 15 years.

An interesting consequence of this is that next Easter is more likely to be earlier than later.
earlier: 50 weeks + 51 weeks = 64%
later: 54 weeks + 55 weeks = 36%
A lot more likely.

Meanwhile 52 and 53 week gaps never happen.
But why is that?

As usual with Easter it's all because of the Moon.

Specifically it's because full moons occur 29½ days apart (more accurately 29.531 days) and 29½s don't divide exactly into one year. 12 full moons take 354 days and 13 full moons take 384 days, near enough, neither of which are anywhere close to 364 days.

Ecclesiastically speaking, Easter is always the first Sunday after the first full moon after the spring equinox. So by the time a year's gone round, the full moon which triggers Easter is always about 10 days earlier or 20 days later, never ever around the same time.

If there are 12 full moons, i.e. 354 days, the gap between Easters will always be 350 or 357 days.
If there are 13 full moons, i.e. 384 days, the gap between Easters will always be 378 or 385 days.
The reason 378 day gaps are rare is because 384 days is a lot closer to 385 than 378.

Looking carefully at the sequence of gaps reveals a few more patterns.

» A 50 week gap is always followed, the next year, by a later Easter.
» A 55 week gap is always followed, the next year, by an earlier Easter.
» Sometimes you get two 51 week gaps in a row, but never three.
» A 54 week gap is always preceded, and followed, by a 51 week gap.

Finally, as you might expect with a 22nd March-25th April window, the date of Easter affects what the next gap is.

If Easter is between 22nd and 28th March, next Easter is always 55 weeks later.
If Easter is between 29th March and 2nd April, next Easter could be 54 or 55 weeks later.
That's us this year, with a 55 week gap until Easter 2025.

If Easter is 3rd, 4th or 5th April, next Easter could be 51, 54 or 55 weeks later.
If Easter is 6th or 7th April, next Easter could be 50, 51 or 54 weeks later.
And if Easter is between 8th and 25th April, next Easter could be 50 or 51 weeks later.

Two conclusions I hope it's been worth waiting for...
If Easter is before 3rd April, next Easter will always be later.
If Easter is after 7th April, next Easter will always be earlier.
And a final corollary which I think is worth knowing.
There can never be two consecutive March Easters.
So we can at least hope next Easter will be a bit warmer.

...or read more in my monthly archives
Jan24  Feb24  Mar24  Apr24
Jan23  Feb23  Mar23  Apr23  May23  Jun23  Jul23  Aug23  Sep23  Oct23  Nov23  Dec23
Jan22  Feb22  Mar22  Apr22  May22  Jun22  Jul22  Aug22  Sep22  Oct22  Nov22  Dec22
Jan21  Feb21  Mar21  Apr21  May21  Jun21  Jul21  Aug21  Sep21  Oct21  Nov21  Dec21
Jan20  Feb20  Mar20  Apr20  May20  Jun20  Jul20  Aug20  Sep20  Oct20  Nov20  Dec20
Jan19  Feb19  Mar19  Apr19  May19  Jun19  Jul19  Aug19  Sep19  Oct19  Nov19  Dec19
Jan18  Feb18  Mar18  Apr18  May18  Jun18  Jul18  Aug18  Sep18  Oct18  Nov18  Dec18
Jan17  Feb17  Mar17  Apr17  May17  Jun17  Jul17  Aug17  Sep17  Oct17  Nov17  Dec17
Jan16  Feb16  Mar16  Apr16  May16  Jun16  Jul16  Aug16  Sep16  Oct16  Nov16  Dec16
Jan15  Feb15  Mar15  Apr15  May15  Jun15  Jul15  Aug15  Sep15  Oct15  Nov15  Dec15
Jan14  Feb14  Mar14  Apr14  May14  Jun14  Jul14  Aug14  Sep14  Oct14  Nov14  Dec14
Jan13  Feb13  Mar13  Apr13  May13  Jun13  Jul13  Aug13  Sep13  Oct13  Nov13  Dec13
Jan12  Feb12  Mar12  Apr12  May12  Jun12  Jul12  Aug12  Sep12  Oct12  Nov12  Dec12
Jan11  Feb11  Mar11  Apr11  May11  Jun11  Jul11  Aug11  Sep11  Oct11  Nov11  Dec11
Jan10  Feb10  Mar10  Apr10  May10  Jun10  Jul10  Aug10  Sep10  Oct10  Nov10  Dec10
Jan09  Feb09  Mar09  Apr09  May09  Jun09  Jul09  Aug09  Sep09  Oct09  Nov09  Dec09
Jan08  Feb08  Mar08  Apr08  May08  Jun08  Jul08  Aug08  Sep08  Oct08  Nov08  Dec08
Jan07  Feb07  Mar07  Apr07  May07  Jun07  Jul07  Aug07  Sep07  Oct07  Nov07  Dec07
Jan06  Feb06  Mar06  Apr06  May06  Jun06  Jul06  Aug06  Sep06  Oct06  Nov06  Dec06
Jan05  Feb05  Mar05  Apr05  May05  Jun05  Jul05  Aug05  Sep05  Oct05  Nov05  Dec05
Jan04  Feb04  Mar04  Apr04  May04  Jun04  Jul04  Aug04  Sep04  Oct04  Nov04  Dec04
Jan03  Feb03  Mar03  Apr03  May03  Jun03  Jul03  Aug03  Sep03  Oct03  Nov03  Dec03
Jan02  Feb02  Mar02  Apr02  May02  Jun02  Jul02 Aug02  Sep02  Oct02  Nov02  Dec02

Life viewed from London E3

Apr24  Mar24  Feb24  Jan24
Dec23  Nov23  Oct23  Sep23
Aug23  Jul23  Jun23  May23
Apr23  Mar23  Feb23  Jan23
Dec22  Nov22  Oct22  Sep22
Aug22  Jul22  Jun22  May22
Apr22  Mar22  Feb22  Jan22
Dec21  Nov21  Oct21  Sep21
Aug21  Jul21  Jun21  May21
Apr21  Mar21  Feb21  Jan21
Dec20  Nov20  Oct20  Sep20
Aug20  Jul20  Jun20  May20
Apr20  Mar20  Feb20  Jan20
Dec19  Nov19  Oct19  Sep19
Aug19  Jul19  Jun19  May19
Apr19  Mar19  Feb19  Jan19
Dec18  Nov18  Oct18  Sep18
Aug18  Jul18  Jun18  May18
Apr18  Mar18  Feb18  Jan18
Dec17  Nov17  Oct17  Sep17
Aug17  Jul17  Jun17  May17
Apr17  Mar17  Feb17  Jan17
Dec16  Nov16  Oct16  Sep16
Aug16  Jul16  Jun16  May16
Apr16  Mar16  Feb16  Jan16
Dec15  Nov15  Oct15  Sep15
Aug15  Jul15  Jun15  May15
Apr15  Mar15  Feb15  Jan15
Dec14  Nov14  Oct14  Sep14
Aug14  Jul14  Jun14  May14
Apr14  Mar14  Feb14  Jan14
Dec13  Nov13  Oct13  Sep13
Aug13  Jul13  Jun13  May13
Apr13  Mar13  Feb13  Jan13
Dec12  Nov12  Oct12  Sep12
Aug12  Jul12  Jun12  May12
Apr12  Mar12  Feb12  Jan12
Dec11  Nov11  Oct11  Sep11
Aug11  Jul11  Jun11  May11
Apr11  Mar11  Feb11  Jan11
Dec10  Nov10  Oct10  Sep10
Aug10  Jul10  Jun10  May10
Apr10  Mar10  Feb10  Jan10
Dec09  Nov09  Oct09  Sep09
Aug09  Jul09  Jun09  May09
Apr09  Mar09  Feb09  Jan09
Dec08  Nov08  Oct08  Sep08
Aug08  Jul08  Jun08  May08
Apr08  Mar08  Feb08  Jan08
Dec07  Nov07  Oct07  Sep07
Aug07  Jul07  Jun07  May07
Apr07  Mar07  Feb07  Jan07
Dec06  Nov06  Oct06  Sep06
Aug06  Jul06  Jun06  May06
Apr06  Mar06  Feb06  Jan06
Dec05  Nov05  Oct05  Sep05
Aug05  Jul05  Jun05  May05
Apr05  Mar05  Feb05  Jan05
Dec04  Nov04  Oct04  Sep04
Aug04  Jul04  Jun04  May04
Apr04  Mar04  Feb04  Jan04
Dec03  Nov03  Oct03  Sep03
Aug03  Jul03  Jun03  May03
Apr03  Mar03  Feb03  Jan03
Dec02  Nov02  Oct02  Sep02
back to main page

the diamond geezer index
2023 2022
2021 2020 2019 2018 2017
2016 2015 2014 2013 2012
2011 2010 2009 2008 2007
2006 2005 2004 2003 2002

my special London features
a-z of london museums
E3 - local history month
greenwich meridian (N)
greenwich meridian (S)
the real eastenders
london's lost rivers
olympic park 2007
oranges & lemons
random boroughs
high street 2012
river westbourne
trafalgar square
capital numbers
east london line
lea valley walk
olympics 2005
regent's canal
square routes
silver jubilee
unlost rivers
cube routes
Herbert Dip
metro-land
capital ring
river fleet
bakerloo

ten of my favourite posts
the seven ages of blog
my new Z470xi mobile
five equations of blog
the dome of doom
chemical attraction
quality & risk
london 2102
single life
boredom
april fool

ten sets of lovely photos
my "most interesting" photos
london 2012 olympic zone
harris and the hebrides
betjeman's metro-land
marking the meridian
tracing the river fleet
london's lost rivers
inside the gherkin
seven sisters
iceland

just surfed in?
here's where to find...
diamond geezers
flash mob #1  #2  #3  #4
ben schott's miscellany
london underground
watch with mother
cigarette warnings
digital time delay
wheelie suitcases
war of the worlds
transit of venus
top of the pops
old buckenham
acorn antiques
digital watches
outer hebrides
olympics 2012
school dinners
pet shop boys
west wycombe
bletchley park
george orwell
big breakfast
clapton pond
san francisco
thunderbirds
routemaster
children's tv
east enders
amsterdam
little britain
credit cards
jury service
big brother
jubilee line
number 1s
titan arum
typewriters
doctor who
coronation
blue peter
matchgirls
hurricanes
buzzwords
brookside
monopoly
peter pan
starbucks
feng shui
leap year
manbags
bbc three
vision on
meridian
concorde
wembley
islington
ID cards
bedtime
freeview
beckton
eclipses
letraset
arsenal
sitcoms
gherkin
calories
everest
muffins
sudoku
camilla
london
ceefax
robbie
becks
dome
BBC2
paris
lotto
118
itv