Easter on the Move

Wondering why the date of Easter changes every year? The answer is a fascinating blend of history, natural phenomena, and the deep hope at the heart of the Christian faith. The Rev. Michael Bird explains. 

Easter has a way of sneaking up on us. This year, it falls on April 5. Last year, it was April 20, and in 2027 it lands on March 28. These shifts can feel almost whimsical, as though Easter wanders around our calendar at will. But Easter’s date is anything but random, says Trinity’s vicar, the Rev. Michael Bird.  

“It’s essentially an ancient and consequential math problem,” Father Michael says. “And if you look closely, this calculation illustrates some profound truths about our faith.” 

In the first few centuries after Jesus's earthly life, Christians did not have a unified stance on the timing of Easter, debating whether the holiday should follow the Jewish calendar or always land on Sunday. On one hand, all four Gospels tell us Jesus rose on the first day of the week. Yet Easter is also inseparable from Passover, the festival Jesus and his disciples observed at the Last Supper. In the Jewish lunisolar calendar (a system that uses both the moon and sun to track time), Passover coincides with a full moon on the fifteenth day of the month of Nisan — a date that maps differently onto our liturgical calendar every year (and not always on a Sunday). This issue of how to calculate Easter’s date mattered deeply to early Christians, whose far-flung and growing church needed a shared understanding of when all would celebrate the holiest day in their calendar.  

The Council of Nicaea in 325 CE, the church’s first ecumenical bishops’ meeting, provided some clarity. Church leaders decided Easter would be celebrated on the first Sunday after the first full moon following the spring equinox. This formula sounds almost comically complex today, but it was designed to honor both the biblical narrative and the natural world. It preserves Easter’s connection to Passover’s lunar timing and ensures the celebration always happens on a Sunday.  

Since the spring equinox typically falls around March 20 or 21, Easter can land anywhere between March 22 and April 25. Early Easters are rare — the most recent March 22 celebration was in 1818, and it won’t happen again until 2285. We’ll experience the opposite end of the spectrum in just 12 years, when Easter falls on April 25, 2038. The last Easter on that date was in 1943. 

All these threads — history, astronomy, theology — come together to form layers of spiritual meaning. Tying Easter to Passover reminds us Jesus was a Jew and that an infinite, universal God chose to be revealed to us through a particular person, in a particular time and place, says Father Michael. Linking Easter to the spring equinox underscores the Resurrection as a turning point — the moment in the year that the earth begins to warm, days lengthen, and new growth pushes through the soil, reminding us that Jesus opens the way to eternal life.  

Finally, celebrating Easter on the first day of the week marks the Resurrection as the start of a new way of belonging to God and one another. Remembering this promise, Easter has long been a traditional time for baptisms and for those already baptized to renew the vows that seal us into God’s family. 

As we trace the winding path by which Christians came to mark this feast, we see that Easter’s movement carries meaning. “Easter changes everything,” says Father Michael. It beckons us to look back to the roots of our faith, notice the rhythms of creation, and look forward with hope.  

“When you realize how carefully early Christians worked to determine the date of Easter, you begin to see just how deeply it mattered to them and to us,” he adds. “Easter brings us face to face with the deepest truth of all: Nothing can separate us from the love of God. If we can open ourselves to that reality, our lives are changed forever.” 

Learn more about Lent at Trinity Church.