In addition to every Sunday, the days to be observed as holy days of obligation in the Latin rite arch/dioceses of the United States of America include the following solemnities: Mary, Mother of God (January 1); the Ascension of the Lord (Forty Days after Easter); the Assumption of the Blessed Virgin Mary (August 15); All Saints (November 1); Nativity of the Lord [Christmas] (December 25).
Whenever January 1, the solemnity of Mary, the Mother of God; or August 15, the solemnity of the Assumption of the Blessed Virgin; or November 1, the solemnity of All Saints falls on a Saturday or on a Monday, the obligation to attend Mass is lifted. The faithful, however, are encouraged to attend Mass on those days.
Please note that the 2025 Holy Days of Obligation will be posted soon.