When is Easter

Easter can fall anywhere in a thirty-five-day window, and the whole spring calendar moves with it.

The rule

Easter Day is the first Sunday after the first full moon on or after 21 March. Not the astronomical full moon, but the ecclesiastical one — a value from a table that approximates the moon and, crucially, is the same everywhere, so the whole Western church keeps the feast on the same day without observing the sky.

That puts Easter between 22 March and 25 April: a window of thirty-five days. Everything from Ash Wednesday to Pentecost hangs off it, so a parish’s spring can differ by more than a month from one year to the next.

The dates

Computed with the Meeus/Jones/Butcher algorithm — the same code that resolves every Sunday on this site, so these dates and the lectionary pages cannot disagree.

What moves with it

What does not

Christmas, the Epiphany, Candlemas and the Annunciation are fixed to calendar dates. Advent Sunday hangs off Christmas, not Easter. The consequence is that the length of Ordinary Time after Trinity absorbs all the variation — an early Easter gives a long green season, a late one a short one, and that is why the Proper numbering in the autumn shifts.

Why Orthodox Easter is often different

The Orthodox churches apply the same rule using the Julian calendar, which now runs thirteen days behind the Gregorian. The two coincide in some years and diverge by up to five weeks in others.

Questions

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