The Church’s Code of Canon Law includes the ascension of Jesus among the solemn feast days to be observed by Latin-rite Catholics throughout the universal Church. The text also remarks, “The conference of bishops can abolish certain holy days of obligation or transfer them to a Sunday with the prior approval of the Apostolic See” (Canon 1246.2).
In many places, as we have seen, the Ascension has been transferred to Sunday, and for a twofold reason. First, holy days are to be observed with the same regard as Sundays. The Catechism of the Catholic Church notes, “On Sundays and other holy days of obligation, the faithful are to refrain from engaging in work or activities that hinder the worship owed to God … and [partake in] the appropriate relaxation of mind and body” (No. 2185). This is often impossible on weekdays, so moving the feast to a Sunday makes a great deal of sense.
Some will ask why the Church does not maintain the feast of the Ascension on Thursday but remove the obligation to attend Mass that day. This leads to the second reason for moving the feast. Doing so allows those who cannot attend Mass on Thursday to share an important, common prayer experience.