The Feast of the Immaculate Conception is normally celebrated on December 8, exactly nine months before the  Nativity of the Blessed Virgin Mary (September 8). However, because the celebration of the Immaculate Conception falls on the Second Sunday of Advent this year, the feast is transferred to December 9. While the Solemnity of the Immaculate Conception is a  Holy Day of Obligation (even when December 8 falls on a Saturday or Monday), the obligation is abrogated when the celebration of the feast is transferred to December 9.