Why does the date of easter change every year?

Easter sunday. There is no set date, but a set DAY.

• Advice Girl, (:

The date of Easter changes every year, because the school district the Easter Bunny resides in keeps changing spring break every year, and he and Mrs. Bunny like to spend spring break with the kids.

…plus, something to do with ancient solar deities and the celebration of Oester upon which Easter is based.

It has to do with some old calendar calculations

From the Wiki entry on Easter:

The First Council of Nicaea (325) established the date of Easter as the first Sunday after the full moon following the vernal equinox.

Ecclesiastically, the equinox is reckoned to be on March 21 (regardless of the astronomically correct date), and the full moon is not necessarily the astronomically correct date. The date of Easter therefore varies between March 22 and April 25. Eastern Christianity bases its calculations on the Julian Calendar whose March 21 corresponds, during the twenty-first century, to April 3 in the Gregorian Calendar, in which calendar their celebration of Easter therefore varies between April 4 and May 8.

It changes every year because the church calender doesn’t have a set date. Also easter is always on a sunday and we all know that the date of a sunday in April is not going to be the same every year. I

It’s always the weekend after the full moon of equinox.