How is the Date of Easter Determined?

Every year I scramble for the calendar when March approaches. Why? Because I never know when Easter will be. Since the actual date of Easter Sunday changes every year and can fall anywhere from late March to the end of April, I am always at a loss. Why does the date change every year? And how is that date determined? According to Christian religions, Easter is the day that celebrates the resurrection of Jesus Christ after his death on the cross. Easter falls at the end of 40 days of Lent and is always the Sunday after Good Friday, which commemorates the death of Christ. But, how is the particular date determined each year?

To understand the reason the date changes, we must look back at the time of Christ. The Last Supper occurred the day before Christ's crucification. This Last Supper was on the Jewish holiday of Passover. This Passover fell on the paschal full moon which was 14 days after the vernal (or Spring) equinox.

The Council of Nicaea in AD 325 set the official date of Easter as the first Sunday after the paschal full moon. This date should coincide with the same date, in history, when Jesus was resurrected. However, since the vernal equinox can actually fall on different dates depending upon your time zone, the church set the official date of the equinox as March 21^st, regardless of the year. The next full moon after the equinox is the paschal full moon. Easter falls the first Sunday after that full moon.

Since the first full moon after the equinox changes each year, the date of Easter changes as a result. This is why the date of Easter is different each year. Sound confusing? It can be. Eastern Orthodox religions actually use different dating. However, the traditional Gregorian calendar used in both secular and religious aspects of the Western world is the date that is most often celebrated as Easter. The following dates are the dates for the paschal full moon and Easter for the years of 2009, 2010 and 2011. For each year after that, you can look up the date of the first full moon after March 21^st and then look for the first Sunday after that date to determine Easter Sunday.

In 2009, the first full moon after March 21^st is on April 9^th. Therefore, Easter falls that following Sunday, April 12^th.

In 2010, the first full moon after March 21^st will be on March 30^th. Therefore, Easter of 2010 will fall on April 4^th.

In 2011, the first full moon after March 21^st will be on April 18^th. Therefore, Easter of 2011 will fall on April 24^th.

Sources:

Full Moons 2007-2012

http://www.ewpnet.com/full-moon.htm

Catholicism.about.com

How Is the Date of Easter Calculated?

http://catholicism.about.com/od/holydaysandholidays/f/Calculate_Date.htm

Christianity.about.com

What is Easter?

http://christianity.about.com/od/holidaytips/qt/whatiseaster.htm