Why is Easter on a different date every year? We look to the moon for answers

Why is Easter on a different date every year? We can look to the moon for answers. Like astronomy and religion themselves, determining the date of Easter can get complicated.

When will Easter take place this year?

This year Easter will take place on March 31, 2024.

For non-Orthodox Christians, Easter can never occur before March 22 or later than April 25, according to the Astronomical Applications Department.

Eastern Orthodox Christians will celebrate the holy day on Sunday, May 5 this year.

How does the moon affect what day Easter is?

Easter changes each year depending somewhat on the moon's schedule.

Every year, the Christian holiday coincides with the first Sunday after the first full moon of spring, according to Almanac.com.

This year, the vernal equinox occurs on March 19, with the first full moon of spring taking place on March 25. A quick check of the calendar puts Easter on March 31, the first Sunday after the first full moon of spring, also called the Paschal Moon.

Why does Easter change each year and why is it sometimes late?

Using the moon to determine the date of Easter is only part of the story because the Christian church has a fixed date for the start of spring — March 21, which is called the ecclesiastical date. That date doesn't always line up with the astronomical start of spring known as the vernal equinox.

This can lead to a late Easter, which last happened in 2019 when ecclesiastical full moon occurred before the ecclesiastical vernal equinox, meaning Easter could not be observed until a full lunar cycle later when the Paschal full moon emerged in mid-April. So that's why Easter was celebrated on Sunday, April 21 in 2019, according to Almanac.com.

Astronomers and Christian church leaders use different calendars to determine the lunar cycle, according to Almanac.com.Because the lunar cycles determined by the church were set in the year 325, the the date of the ecclesiastical full Moon may be one or two days off from the date of the astronomical full Moon.

What is the Paschal full moon?

The word Paschal stems from the Greek and Latin words for "passover."

The Paschal full moon is always the first full moon to take place after the vernal equinox. This year it will take place on March 25.

This year the Jewish holiday of Passover will take place April 22, and ends on the evening of Tuesday, April 30. The Seder feast is held the first two nights of Passover and will be April 22-24 this year.

Cheryl McCloud, USA TODAY Network-Florida, contributed to this story

This article originally appeared on Florida Today: How is Easter 2024 date determined and why does it change each year?