Thanks to the way the dates shift around each year, Easter celebrations at home can be hard to plan for.
Here are the key dates for your diary for 2020 which should make things a little easier.
When is Easter 2020?
Unlike Halloween, New Year or Christmas, Easter doesn’t have a set date on which it falls every year.
It can fall any time between 22 March and 22 April.
In 2020, Easter Sunday will be on 12 April, which will make Good Friday 10 April and the Easter Monday bank holiday 13 April.
Why does the date of Easter change?
Easter Sunday is decided based on a complicated set of calculations regarding observations of the moon.
The exact date on which Easter should be celebrated is something churches have debated for centuries, with various methods of calculation used by different sects.
To this day, churches in the east date Easter differently than those in the west, although sometimes the dates will coincide. In 2020, eastern churches will celebrate Easter on Sunday 19 April.
2025 will be the next year in which both hemispheres celebrate Easter at the same time.
How is the date chosen?
The decision on when Easter should fall each year was made in 325 AD by the first major church council, the Council of Nicaea.
The Bible dates Easter to around the time of the Jewish festival of Passover, which usually begins on the night of the first full moon after the Spring Equinox (one of the two moments in the year at which time the sun is directly above the equator).
However, during “leap months” – the extra month added during leap years according to the Jewish calendar to make up for the fact that the solar year is actually slightly longer than 12 months – Passover begins on the second full moon after the equinox rather than the first.
While 2020 is a leap year according to the Gregorian calendar, it's not a leap year according to the Jewish calendar, so Passover will begin on the first full moon – Wednesday 8 April.
Easter takes place around the time The Bible records it as having occurred, so it's celebrated on the first Sunday after the first full moon on or after the Spring Equinox.
However, things become a little more complicated once you take into consideration the fact that moon observations vary depending on which time zone they are conducted from. In an attempt to standardise things, churches in the west use the ecclesiastical full moon instead.
The ecclesiastical calendar breaks 19 normal calendar years down into 235 months made up of 30 or 29 days. It places the full moon at the 14th day of each month and terms the first full moon after the Equinox the “paschal full moon.”
Easter is the first Sunday to fall after this full moon, meaning that if the paschal full moon falls on a Sunday, Easter will be the following week.
Churches in the east celebrate Easter on a different date because they use the Julian calendar which is 13 days behind the one used in the west.
This article originally appeared on our sister site, The Scotsman.