In the Catholic Church, Holy Days of Obligation are the days on which the faithful are obliged to participate in the Mass. They must also abstain from unnecessary works, "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 of the Code of Canon Law).
The list of Days of Obligation includes all Sundays in all countries. Some feasts, e.g. Easter, are always celebrated on Sundays, so they are always obligatory. The number of additional Days of Obligation vary between countries, from 1 in Hong-Kong to 10 in Vatican.
|Date||Holiday name||Is obligatory in 2015?|
|All Sundays are obligatory for the faithful to participate in the Mass|
|Thursday, January 1, 2015||Solemnity of Mary, Mother of God||Yes|
|Thursday, May 14, 2015||Ascension of Jesus||Yes|
|Saturday, August 15, 2015||Assumption of the Blessed Virgin Mary||No|
|Sunday, November 1, 2015||All Saints' Day||Yes|
|Tuesday, December 8, 2015||Feast of the Immaculate Conception||Yes|
|Friday, December 25, 2015||Christmas||Yes|