The proclamation of the date of Easter and the other moveable feasts on Epiphany dates from a time when calendars were not readily available. It was necessary to make known the date of Easter in advance, since many celebrations of the liturgical year depend on its date. The number of Sundays that follow Epiphany, the date of Ash Wednesday, and the number of Sundays that follow Pentecost are all computed in relation to Easter.
Although calendars now give the date of Easter and the other feasts in the liturgical year for many years in advance, the Epiphany proclamation still has value. It is a reminder of the centrality of the resurrection of the Lord in the liturgical year and the importance of the great mysteries of faith which are celebrated each year.
Know, dear brothers and sisters,
that, as we have rejoiced at the Nativity of our Lord Jesus Christ, so by leave of God’s mercy we announce to you also the joy of his Resurrection, who is our Savior.
On the sixth day of March will fall Ash Wednesday,
and the beginning of the fast of the most sacred Lenten season.
On the twenty-first day of April you will celebrate with joy Easter Day, the Paschal feast of our Lord Jesus Christ.
On the second day of June will be the Ascension of our Lord Jesus Christ.
On the ninth day of June, the feast of Pentecost.
On the twenty-third day of June, the feast of the Most Holy Body and Blood of Christ.
On the first day of December, the First Sunday of the Advent of our Lord Jesus Christ, to whom is honor and glory for ever and ever.
Amen.
Source: www.usccb.org