We look forward to celebrating Easter each year. It’s a time of new beginnings and rebirth. Spring definitely fits the bill. But why does the date on which we celebrate Easter change each year?

The short answer is that early Christians wanted to keep the celebration of the resurrection of Jesus Christ as close as possible to when it happened – during the Jewish Passover. This only seemed right. After all, Jesus is the ultimate Passover Lamb, giving us eternal, everlasting life. “The next day John saw Jesus coming toward him and said, ‘Look! The Lamb of God who takes away the sin of the world!'” John 1:29

Passover, and therefore Easter, changes every year because the Jewish calendar is based on solar and lunar cycles. This makes the dates shift from year to year.

Now for the long answer. Easter in Western Christianity is celebrated on the Sunday immediately following the Paschal Full Moon each year. To confuse you, this is not the date of the actual full moon which only happens in reality for a few minutes each cycle. To confuse you a little more, it is not even correlated with the first full moon after the spring equinox. That would be too easy!

Prior to 325 A.D. the date was based on the spring equinox directly. However, after the Council of Nicea met in 325 A.D. the church chose to standardize the system of determining the date of Easter a little more. Thus, they established the Paschal Full Moon.

The date of the Paschal Full Moon is actually determined by historical tables, not lunar events. As astronomers were able to approximate the dates of all the full moons in future years, the Western Christian Church used these calculations to establish a table of Ecclesiastical Full Moon dates. These dates would determine the Holy Days on the Ecclesiastical calendar.

According to the Ecclesiastical tables, the Paschal Full Moon is the first Ecclesiastical Full Moon date after March 20 (which happened to be the spring equinox date in 325 A.D.). In Western Christianity, Easter is always celebrated on the Sunday immediately following the Paschal Full Moon.

The Paschal Full Moon can vary as much as two days from the date of the actual full moon, with dates ranging from March 21 to April 18. As a result, Easter dates can range from March 22 through April 25 in Western Christianity.

This still closely corresponds with the Jewish Passover celebration. This year Easter is April 5 and Passover runs from April 3 to April 11. This lends so much meaning to the celebration of Easter. The entire history of Passover throughout the Old Testament foreshadows the one sacrificial Lamb that would pay the price for our sins once and for all.

“God will also count us as righteous if we believe in him, the one who raised Jesus our Lord from the dead. He was handed over to die because of our sins, and he was raised to life to make us right with God.” Romans 4:24-25