Holy Days of Obligation
On Sundays and other holydays of obligation, the faithful are obliged to participate in Mass. Insofar as possible, they are also to abstain from those works and affairs which hinder the worship to be rendered to God, the joy proper to the Lord’s Day, or the suitable relaxation of mind and body (canon 1247).
By decision of the United States Conference of Bishops and confirmation by the Holy See, whenever the Solemnities of Mary, Mother of God (January 1), the Assumption of the Blessed Virgin Mary (August 15), or All Saints (November 1) fall on a Saturday or a Monday, the obligation to attend Mass is lifted. However, parishes are to continue to observe these holydays by scheduling one or more Masses for the faithful.
All Sundays of the year
Solemnity of Mary, Mother of God (January 1)
Ascension of Our Lord (Seventh Sunday of Easter)
Assumption of the Blessed Virgin Mary (August 15)
All Saints (November 1)
Immaculate Conception of the Blessed Virgin Mary (December 8)
Christmas, the Nativity of Our Lord (December 25)
Holy Days are all listed on the Diocesan Calendar.