There is an ancient practice of the Church, dating back to the time when Christians did not have calendars, in which the moveable feasts of the Church year are announced during the Mass on the Feast of the Epiphany. This carries down to today with the text available in the Roman Missal …
The announcement is chanted by a deacon or cantor after the proclamation of the Gospel:
Know, dear brethren (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 fourteenth day of February will fall Ash Wednesday,
and the beginning of the fast of the most sacred Lenten season.
On the thirty-first day of March you will celebrate with joy Easter Day,
the Paschal feast of our Lord Jesus Christ.
[In those places where the Ascension is observed on Thursday:
On the ninth day of May will be the Ascension of our Lord Jesus Christ.]
[In those places where the Ascension is transferred to the Seventh Sunday of Easter:
On the twelfth day of May will be the Ascension of our Lord Jesus Christ.]
On the nineteenth day of May, the feast of Pentecost.
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
