Holy days of obligation (also known as feasts of precept) are days when the faithful are obliged to participate at Mass and abstain from unnecessary work or other activities which hinder the suitable relaxation of mind and body. Each Sunday is a holy day of obligation, and six Solemnities are also observed as feasts of precept in the United States.
January 1, the solemnity of Mary, Mother of God
Thursday of the Sixth Week of Easter, the solemnity of the Ascension
August 15, the solemnity of the Assumption of the Blessed Virgin Mary
November 1, the solemnity of All Saints
December 8, the solemnity of the Immaculate Conception
December 25, the solemnity of the Nativity of Our Lord Jesus Christ
Whenever January 1, the solemnity of Mary, Motherf of God, or August 15, the solemnity of the Assumption, or November 1, the solemnity of All Saints, falls on a Saturday or on a Monday, the precept to attend Mass is abrogated.