December 2021
| Day | Date | Celebration | Rank |
|---|---|---|---|
| Day | Date | Celebration | Rank |
| Wednesday | 1 | Weekday of Advent | |
| Thursday | 2 | Weekday of Advent | |
| Friday | 3 | St Francis Xavier, Priest | memorial |
| Saturday | 4 |
Weekday of Advent, St John Damascene, Priest, Doctor of the Church |
|
| Sunday | 5 | 2nd Sunday of Advent | Week II |
| Monday | 6 |
Weekday of Advent, St Nicholas, Bishop |
|
| Tuesday | 7 | St Ambrose, Bishop, Doctor of the Church | memorial |
| Wednesday | 8 | The Immaculate Conception of the Blessed Virgin Mary | solemnity |
| Thursday | 9 |
Weekday of Advent, St Juan Diego Cuahtlatoatzin |
|
| Friday | 10 |
Weekday of Advent, Our Lady of Loreto St John Roberts, Priest, Martyr (W) |
|
| Saturday | 11 |
Weekday of Advent, St Damasus I, Pope |
|
| Sunday | 12 | 3rd Sunday of Advent | Week III |
| Monday | 13 | St Lucy, Virgin, Martyr | memorial |
| Tuesday | 14 | St John of the Cross, Priest, Doctor of the Church | memorial |
| Wednesday | 15 | Weekday of Advent | |
| Thursday | 16 | Weekday of Advent | |
| Friday | 17 | Weekday of Advent | |
| Saturday | 18 | Weekday of Advent | |
| Sunday | 19 | 4th Sunday of Advent | Week IV |
| Monday | 20 | Weekday of Advent | |
| Tuesday | 21 |
Weekday of Advent, St Peter Canisius, Priest, Doctor of the Church |
|
| Wednesday | 22 | Weekday of Advent | |
| Thursday | 23 |
Weekday of Advent, St John of Kanty, Priest |
|
| Friday | 24 | Weekday of Advent | |
| Saturday | 25 | The Nativity of the Lord | solemnity |
| Sunday | 26 | The Holy Family of Jesus, Mary and Joseph | feast |
| Monday | 27 | St John, Apostle, Evangelist | feast |
| Tuesday | 28 | The Holy Innocents, Martyrs | feast |
| Wednesday | 29 |
5th day of Christmas Octave, St Thomas à Becket, Bishop, Martyr |
feast (E) |
| Thursday | 30 | 6th day of Christmas Octave | |
| Friday | 31 |
7th day of Christmas Octave, St Sylvester I, Pope |