According to the Liturgy of the Hours note for the Baptism of the Lord this feast is to be omitted when Epiphany falls on a Sunday with a date of January 7 or 8. In the Ordo for the Archdiocese of Chicago and the dioceses of Joliet and Rockford it is listed for January 9. Which is correct?
The calendar gets complicated at this time of year.
It is a good practice to follow the official Ordo of the place where you are.
My understanding is that the Feast of the Baptism of the Lord, in the newer Ordinary Form calendar, falls today, 9 January. Thus, Christmastide would end in the Novus Ordo and tomorrow will be Tuesday of the 1st Week of Ordinary Time.
In the traditional Extraordinary Form calendar, the Commemoration of the Baptism of the Lord falls on 13 January, which would have been be the Octave of Epiphany. For the Extraordinary Form we are in the Season of or rather Time after Epiphany until Septuagesima on 5 February.