Did you know that the date of Easter—April 1 this year—is tied to the motions of the Moon? It is observed on the Sunday after the Paschal Full Moon. Learn more!
Easter and the Motions of the Moon
Easter Sunday has a curious relationship with the Full Moon.
It always falls on the Sunday after the first Full Moon of springtime. This is called the “Paschal Full Moon.”
For simplicity’s sake, the Church set March 21 as the fixed date of spring (even though the equinox can fall on March 19 or 20).
It’s very simple. Take the year 2018:
- The vernal equinox is March 20, 2018.
- The next full Moon (i.e., the first full Moon of spring) is Saturday, March 31.
- The following Sunday is April 1. So, April 1 is Easter Sunday!
Interestingly, Easter Sunday will slip into April for the next six years. It won’t be in March again until 2024!
The Paschal Full Moon date was determined by calculations made in A.D. 325 that did not consider all factors of lunar motion, so it may differ from the actual full Moon date by a day or so.
For those western Christian churches and others that use the Gregorian calendar for their calculations, Easter can occur as early as March 22 and as late as April 25.
For those Eastern Orthodox churches and others that use the Julian calendar for their calculations, the observance can occur between April 3 and May 10 on the Gregorian calendar.
Learn more about how to calculate the date of Easter.
Which Full Moon is Nearest to Easter?
The Full Moon nearest to Easter can change. Sometimes, it’s the full Moon which falls in March and sometimes it’s the full Moon which falls in April.