Easter is not celebrated on a fixed date: it can fall from March 22 to April 25. To establish the exact date of Easter you have to pay attention to the lunar cycle and the spring equinox.
Steps
Part 1 of 3: Establish the Easter Date
Step 1. Mark the date of the vernal equinox
The date of Easter is calculated on the basis of the ecclesiastical approximation of the vernal equinox. This approximation falls on the same day every year: March 21st.
- This calculation is based on the ecclesiastical estimate of the vernal equinox and not on the actual one identified by astronomical observations. The actual time of the equinox can vary within a 24-hour margin, and can also occur the day before March 21st. This fact is not taken into account when calculating the date of Easter.
- We are talking about the vernal equinox for the northern hemisphere. For those living in the southern hemisphere, the date of the autumn equinox must be used. In any case, it is the same date in both hemispheres (March 21).
Step 2. Find the date of the first full moon
Find the date of the first full moon immediately following the vernal equinox. This date can fall a maximum of one month after the equinox itself.
You can find this information by checking a lunar calendar. These calendars report the phases of the moon day by day; you can buy a wall or table one, or rely on one of the many free calendars you can find online
Step 3. Then move on to the following Sunday
The Sunday following the first full moon after the vernal equinox is the date of Easter.
For example, in 2014 the first full moon after the equinox was April 15. This is why Easter 2014 fell on the following Sunday, April 20
Step 4. Be careful if the full moon falls on a Sunday
If the first full moon after the equinox falls on a Sunday, the date of Easter is postponed by one week, until the following Sunday.
- This delay was introduced to decrease the chances of Easter Sunday falling on the same day as Pèsach (Passover).
- For example, in 1994 the first full moon after the equinox was Sunday, March 27. The date of Easter therefore fell the following week, Sunday 3 April.
Part 2 of 3: Establish Easter-Related Dates
Step 1. Go back one week to establish Palm Sunday
Palm Sunday falls exactly one week before Easter.
Palm Sunday commemorates Christ's entry into Jerusalem, and also marks the beginning of Holy Week
Step 2. Pay particular attention to the week between Palm Sunday and Easter
The whole week is often called "Holy Week", but in particular the Thursday, Friday and Saturday immediately preceding Easter represent very important dates in the Christian calendar.
- Holy Thursday celebrates the Last Supper of Christ. It also recalls the "washing of the feet", a biblical moment in which Jesus washed the feet of the Apostles. Many believers of various denominations celebrate the washing of the feet in a religious ceremony.
- Good Friday remembers the day Christ was crucified.
- Holy Saturday commemorates the period when the body of Christ lay in the tomb. It is usually seen as a day of preparation for Easter.
Step 3. Find the Wednesday that falls six weeks before Easter
Find the Sunday that falls six weeks before Easter, and the Wednesday immediately preceding it is Ash Wednesday.
- In other words, Ash Wednesday falls 46 days before Easter.
- Ash Wednesday is a day of repentance in many Christian denominations.
- It also marks the first day of Lent, a 40-day period during which Christians prepare spiritually for Easter.
Step 4. Go 40 days ahead
Ascension Day is a Christian holiday which falls exactly 39 days after Easter Sunday.
The Ascension remembers the moment when Christ ascended into heaven. In some Christian denominations it is considered the "fortieth day of Easter", and the days between Holy Sunday and Ascension are considered part of the Easter season
Part 3 of 3: Additional Considerations
Step 1. Learn the history
Easter has always been celebrated on a date close to that of Pèsach, but the exact method for establishing the date has changed over the centuries.
- Easter is the remembrance of Christ's resurrection after the crucifixion.
- In the Bible, Jesus was resurrected on the Sunday following the Jewish Pèsach. Passover begins on the fifteenth day of the month of Nisan in the Jewish calendar. This roughly corresponds to the first full moon after the March equinox, but the Hebrew calendar is not based on the phases of the moon, so the correspondence is not exact.
- Since the date of Pèsach was to be officially announced each year by the Jewish authorities, early Christian leaders simplified the scheduling of Passover by placing it on the first Sunday after the full moon. This was decided in 325 AD. during the Council of Nicaea.
- The use of the moon and the equinox as a dating system has links to pagan customs. Religious dates had never been decided using astronomical events in the Jewish tradition, from which much of the Christian tradition has emerged. Instead, it is a pagan tradition, adopted by the early Christians in an attempt to simplify their dating system.
Step 2. There are differences between the Gregorian calendar and the Julian calendar
Most Western churches (Roman Catholics and most Protestants) follow the standard calendar, also known as the Gregorian calendar. Some Orthodox Christian churches still use the Julian calendar to establish the date of Easter.
- The Gregorian calendar was created when astronomers realized that the Julian calendar was too long. The dates of the two calendars are similar, but not identical.
- The Gregorian calendar is best aligned with the equinox.
Step 3. Remember the time frame
According to both calendars, Easter always falls between March 22 and April 25.
However, this time span does not fall on the same days. If you look at the Gregorian calendar, Easter established according to the Julian calendar would fall between April 3 and May 10
Step 4. Pay attention to possible reforms
Many churches and nations have proposed various reforms to the method by which the date of Easter is determined, but to date there have been no changes.
- In 1997 the Ecumenical Council of Churches discussed the possibility of replacing the calculation system used today with a method based more directly on astronomical events. This reform should have taken effect from 2001, but has never been implemented.
- In 1928 the United Kingdom set the date of Easter as the first Sunday after the second Saturday in April, but the reform was never applied.
