"...Easter will occur on Sunday, April 12, 2020. You probably already knew that Easter falls on a different date each year… but why?
Easter and the many church holidays related to it—such as Ash Wednesday, Palm Sunday, Good Friday—are called “moveable feasts,” because they do not fall on a fixed date on the Gregorian calendar, which follows the cycle of the Sun and the seasons. Instead, these days follow a lunisolar calendar, similar to Jewish holidays.
According to a Fourth Century ruling, the date of Easter is set for the first Sunday following the Paschal Full Moon, which is the first full Moon of Spring, occurring on or shortly after the Spring Equinox. March 22 is the earliest Easter can occur on any given year, and April 25 is the latest. If that first spring full Moon occurs on a Sunday, then Easter will be observed on the following Sunday...."
