Good Friday and Easter Sunday coincide with the Jewish observance of Passover in 2020. Easter and the holidays that are related to it are moveable feasts in that they do not fall on a fixed date in the Gregorian or Julian calendars which follow only the cycle of the sun; rather, their dates are determined on a lunisolar calendar similar to the Hebrew calendar. It has come to be the first Sunday after the full moon that occurs on or soonest after 21 March, but calculations vary in East and West.