Mumbai: The dates of Christmas and most of the other Christian festivals do not change throughout the year, Easter on the other hand changes every year and so does Good Friday. This year the Easter falls on April 1, which is also April Fool’s day.
The reason why Easter dates changes is because the Church follows the lunar calendar, the death of Jesus occurred around the Jewish Passover which is traditionally held on the first full moon after the vernal equinox. (The Vernal (Spring) Equinox in the Northern Hemisphere is the Autumnal (Fall) Equinox in the Southern Hemisphere and vice versa)
The full moon varies in each time zone around the world and hence the church decided to use the Lunar calendar, and use the 14th day of the lunar month, the Paschal Full Moon. The following Sunday after the full moon is observed as Easter Sunday. So, based on the date of the full moon, Easter day can be estimated.
Easter is celebrated on Sunday, as Jesus rose from the dead on Sunday, after being crucified on Friday. In 325, it was determined by a council of Christian bishops that Easter Day would always be on a Sunday to commemorate the happy occasion.