Who knows why?

[madog]

I do 

[Lek]

It falls on the first Sunday after the first full moon following the Spring equinox.

[BrianSoddingBoru4]

There's a saying where I'm originally from, 'When the shamrock meets the palm.'  It originally meant the unlikelihood of lasting peace in Northern Ireland, but it's come to mean any event that is extremely unlikely.  The saying refers to Palm Sunday falling on St Patrick's day.  Since the earliest possible date for Easter is 22 March, and Palm Sunday is always the Sunday immediately preceding Easter Sunday, Palm Sunday can indeed fall on 17 March.  In last happened in 1940.

It'll roll round again in 2391.

Boru

[pocaracas]

Why is Easter on a different day every year?

Answer

---

Because it' s dependant on phases of the moon. It's always on the first Sunday after the first full moon, following spring equinox.

---

Did you know?
Orthodox Christians use the moon for Easter like you say, but, since they retain the Julian calendar for their calculations, the "equinox" that was once March 21, is now on April 4 (according to the Gregorian calendar)
Catholic Christians stick to march 21 under the Gregorian calendar.
This makes Orthodox Easter fall one week later than Catholic Easter, most of the time. On a few years, they do both agree.
Protestants, since they hand later, just copied off from Catholics.

[Drich]

Why is Easter on a different day every year?

Answer

---

Because it' s dependant on phases of the moon. It's always on the first Sunday after the first full moon, following spring equinox.

---

which coincides with the passover feast that celebrated the 10th plague that wiped out the egyptian first born and spared the hebrew first born inspiring pharaoh to let moses and the jews go. This is also the in the time of Jesus. His "last supper" before the crucifiction and the on the third he rose/easter.

The pass over feast is still celebrated by the jews every year.