This year Sunday and Monday is all we get of the fourth week of Advent, and then we are into the new season of Nativitytide, which lasts until 13 January.
For those saying the Office, note that Christmas has a Class II Octave, so unlike Easter, you actually do say the psalms of the particular day at Prime and the little hours unless displaced by one of the many feasts this season, viz:
Sunday 23 December – Fourth Sunday of Advent, Class I
Monday 24 December - Vigil of the Nativity, Class I
Tuesday 25 December – The Nativity of Our Lord, Class I with a II Class Octave
Wednesday 26 December – St Stephen, Protomartyr, Class II
Thursday 27 December – St John the Evangelist, Class II
Friday 28 December - Holy Innocents, Martyrs, Class II
Saturday 29 December – Fifth Day within the Octave of the Nativity, Class II [in some places, St Thomas Beckett, Class I]
May you have a happy and holy Christmas.