diamond geezer

 Sunday, April 24, 2011


(Sunday April 24th 2011)

Good morning, Happy Easter, and welcome to the latest Easter Sunday in living memory. It might not be the latest Easter you've ever experienced, if you're over retirement age that is, because Easter fell one day later back in 1943. And it won't be the latest Easter you'll ever experience, assuming you live for another quarter of a century, because it'll fall one day later in 2038 too. But for a sizeable middle-aged proportion of the world's population, Easter on 24th April is as late as it'll ever get.

And here, very simply, is why it's so late. Easter is always the first Sunday after the first full moon after the spring equinox. And this year, 2011, everything in that list has happened really really slowly...

    Equinox*: Monday 21st March
    Full Moon**: Sunday 17th April
    Easter Sunday: Sunday 24th April

There was a full moon on Saturday 19th March (the super full moon, you remember). But 19th March was slightly too early to trigger the date of Easter because the spring equinox hadn't quite taken place. So things skipped ahead 29 days to the next full moon, which was last Sunday 17th April. But the rules state that Easter has to be the next Sunday after the full moon, so here we are on Easter Sunday 24th April.

* Sorry to get complicated, but this year the true spring equinox fell just before midnight GMT on Sunday 20th March. But the church chooses to ignore such astronomical fripperies, because Greenwich never once appears in the Bible, and so takes the date of the equinox as 21st March whatever. Don't worry, be it Sunday 20th or Monday 21st, Easter 2011 would still have ended up being today.
** Sorry to get more complicated, but this year the true Easter full moon occurred around 3am GMT on Monday 18th April. But the church chooses to ignore such astronomical fripperies, because Greenwich never once appears in the Bible, and so takes the date of a "Paschal full moon" on 17th April instead. Don't worry, be it Sunday 17th or Monday 18th, Easter 2011 would still have ended up being today.

The only way to get a later Easter than 24th April is to have full moons on 20th March and 18th April. This happens roughly every 19 years, which is a fairly common event. But we only get the ultimate late Easter when 18th April is a Sunday, delaying Easter until Sunday 25th April. There are seven possible days of the week on which 18th April can fall, and only when it's a Sunday does the ultimate late Easter occur. A one in 19 chance, multiplied by a 1 in 7 chance, that's an event of 1 in 133 year rarity.

Here's a list of really late Easters, so you can see how rare they really are:
Easter on 21st April: last happened 1957, next happens 2019
Easter on 22nd April: last happened 1984, next happens 2057
Easter on 23rd April: last happened 2000, next happens 2079
Easter on 24th April: last happened 1859, next happens 2095 (and this year, of course)
Easter on 25th April: last happened 1943, next happens 2038 (but then not again until 2190)

If you're interested in this sort of thing, do check out the series of detailed "date of Easter" posts I wrote three years ago when there was an extremely early Easter. And if you're not interested in this sort of thing, then just revel in the longest Creme Egg eating season of all time.

Easter trivia
Here are two excellently long lists of Easter dates: 1875 to 2124; 1583 to 3000
The cycle of Easter dates repeats every 5,700,000 years. During this period, Easter falls on 24th April only 81,225 times (less than 1½% of the total).
Although Easter can fall on any date from 22nd March to 25th April, the two most likely dates are 19th April and 18th April.
Almost exactly half of our Easters occur on the same date 11 years later (but never more than four in a row). For example, Easter will fall on 21st April in 2019, 2030, 2041 and 2052, but not in 2063.
Consecutive Easters are always separated by 350, 357, 378, or 385 days (that's 50, 51, 54, or 55 weeks). For example, Easter 2011 is 385 days after Easter 2010, but 350 days before Easter 2012. So we've just had the longest possible gap between Easters, and we're about to enter the shortest.
Until this weekend, the UK's warmest Easter was in 1984, when the temperature in Jersey on 22nd April reached 26°C. Tons more Easter weather records can be found here.
It's extremely unlikely to have an extremely early Easter (2008) so close to an extremely late Easter (2011), and this won't happen again until 2160/2163.

<< click for Newer posts

click for Older Posts >>

click to return to the main page

...or read more in my monthly archives
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 

eXTReMe Tracker
jack of diamonds
Life viewed from London E3

» email me
» follow me on twitter
» follow the blog on Twitter
» follow the blog on RSS

my flickr photostream