Days on which the reading from the lectionary must be used during a Catholic wedding
Ritual Masses are not permitted on Sundays of Advent, Lent, and Easter, on Solemnities, on the days within the Octave of Easter, on All Souls' Day, on Ash Wednesday, and during Holy Week (GIRM #372), and on Holy Days of Obligation*. It is still permissible to celebrate Marriages on these days (except on Good Friday and Holy Saturday), but the assigned prayers and readings of the day’s Mass must be used. Things such as the nuptial blessing, solemn blessing, and one substitute reading exception would be incorporated as outlined in The Order of Celebrating Matrimony #56.
Note that on many of these days, the The Order of Matrimony without Mass may be used with no restrictions.
*The holy days of obligation in most dioceses in the United States are: January 1, the solemnity of Mary, Mother of God; Thursday of the sixth week of Easter, the feast of the Ascension; August 15, the solemnity of the Assumption of the Blessed Virgin Mary; November 1, the feast of All Saints; December 8, the feast of the Immaculate Conception; and December 25, Christmas.
For more information
An overview of how to choose readings for your Catholic wedding, as well as links to a list of suggested readings from the Rite of Marriage.
Check the readings for any day of the year on the current liturgical calendar from the United States Conference of Catholic Bishops. Scroll to the bottom of the page to find the calendar for the year of your wedding.