If you’re reading this on Christmas morning… well, props to you for being a liturgy nerd I guess. And I’ll keep this short so you get back to whatever you’re “supposed to be doing” at this time.
In the 1662 Prayer Book, Christmas Day is one of the six days in the year that gets its own Psalms Appointed, interrupting the 30-day cycle.
Morning Prayer: 19, 45, and 85
Evening Prayer: 89, 110, 132
If at all possible, I strongly encourage you to replace the “Day 25” Psalms with these. It’ll make the Offices a little bit longer, but you will find they are festively appropriate for the birth of our Lord.
And, in case you’re concerned that this means you’ll have to skip the Psalms for the 25th Day of the month, fear not! Because December has 31 days in it, you can pick up with Day 25 on the 26th, Day 26 on the 27th, and so forth such that you finish the Psalms at the end of the month. If you can stand being “off a day” for a week, I highly recommend it.
Anyway, go have a merry Christmas.