According to the particular law of the Archdiocese of Toronto (promulgated since 1971), weddings in the Catholic Church are not allowed to be celebrated on Sundays or Holy Days of Obligation (January 1, the solemnity of Mary, Mother of God and December 25, the solemnity of the Nativity of our Lord Jesus Christ).
[1] Marriage, Ritual and Pastoral Notes (CCCB), no. 21, p.18.