For your easy reference, the following is a list of weeks and years with their corresponding date:
27 Dec 2015 – Holy Family
28 Dec 2015 – The Holy Innocents, Martyrs – Feast
29 Dec 2015 – 5th day within the octave of Christmas
30 Dec 2015 – 6th day within the octave of Christmas
31 Dec 2015 – 7th day within the octave of Christmas
1 Jan 2016 – Mary, Mother of God – Solemnity