Easter Dating Method - Calculate the date of Easter Sunday

Easter Dating Method - Calculate the date of Easter Sunday

Why is it so late this year?

It is the most complicated holiday in the modern calendar. Easter is the first Sunday after the first full moon which falls on or after March 21st, which is a fixed date used by Christians to represent the vernal equinox. (The actual equinox may not fall precisely on that date.) This process was established in 325 AD by the Council of Nicea. Before then it was calculated by the Jewish calendar ("the fourteenth day of the moon, on which day the Jews were commanded to sacrifice the lamb"), and before 190 AD it could even occur on weekdays!

Bottom line, modern Easter can occur as early as March 22nd (which means that the full moon is on March 21st, and March 21st is on a Saturday), and as late as April 25th (which means that the full moon is on April 18th; and that April 18th occurs on a Sunday). This year Easter almost maxxes out. It's on April 24th. Just three years ago it was more thana full month earlier, on March 23rd.

The Orthodox churches use essentially the same method, but base it on their own calendar, so they sometimes match with the Western churches, and sometimes not, depending on whether the full moon occurs in the period between March 21st on our calendar and March 21st on theirs. This year and last year the dates coincide. Next year the Orthodox Easter is a week later than the Western. Their Easter can occur as late as May 8th on our calendar.

Why is the date determined that way? You can get much more detail about the evolution of the process in early Christianity at the Catholic Encyclopedia.

In 2010, Easter fell on the same day as Giant Pink Japanese Penis Day, another celebration of Spring. We have to wait until 2015 for that serendipitous alignment to reoccur. This year GPJPD occurs three weeks earlier than Easter.