The Catholic Church honors the life of St. Joseph, Spouse of the Blessed Virgin Mary, on March 19 every year. It is one of the few jubilant solemnities during the season of Lent and is a time of great rejoicing.
However, this feast of St. Joseph will never supersede a Sunday of Lent. If March 19 happens to fall on a Sunday, it will always be moved to the following Monday, March 20.
The reason behind this is because the Sundays of Advent. Lent, and Easter rank higher than all solemnities. There are occasional local exceptions, such as the permission to celebrate the Feast of Our Lady of Guadalupe on December 12, even if it falls on an Advent Sunday -- but only within the dioceses of Mexico.
During Christmas and Ordinary Time, solemnities and and lesser-ranking feasts of the Lord can be celebrated in place of a Sunday.
If you want to celebrate St. Joseph at Mass when March 19 falls on a Sunday, you'll need to attend Mass on Monday, March 20. If your parish or a local organization is sponsoring a St. Joseph's table celebration, check to see whether it will be held on the 19th or the 20th this year,
