When Does The Liturgical Day Begin & End? - Jimmy Akin

Down yonder, a reader writes:

Hi, I have a question. This has sort of been bothering me, although I undertake a stricter fast this question is mostly academic for me anyway. What are the limits of "Ash Wednesday"? Sundown to sundown? Sundown to sunup on thursday? Midnight to midnight? Whenever you go to bed to whenever you wake up?

Ash Wednesday–like the liturgical day in general–runs from midnight to midnight. According to the General Norms for the Liturgical Year and the Calendar:

3. Each day is made holy through the liturgical celebrations of the people of God, especially through the eucharistic sacrifice and the divine office. The liturgical day runs from midnight to midnight, but the observance of Sunday and solemnities begins with the evening of the preceding day.

Note the difference between the "observance" of certain days beginning on the evening of the preceding day even though they day itself doesn't begin until midnight. 

Ash Wednesday is not a solemnity and so does not have a preceding evening celebration of this sort.

Oh, and for what it's worth, the day also (typically) runs from midnight to midnight in canon law (as opposed to liturgical law). The Code of Canon Law provides:

Can. 202 §1. In law, a day is understood as a period consisting of 24 continuous hours and begins at midnight unless other provision is expressly made; a week is a period of 7 days; a month is a period of 30 days, and a year is a period of 365 days unless a month and a year are said to be taken as they are in the calendar.

§2. If time is continuous, a month and a year must always be taken as they are in the calendar.

Author: Jimmy Akin

Jimmy was born in Texas, grew up nominally Protestant, but at age 20 experienced a profound conversion to Christ. Planning on becoming a Protestant seminary professor, he started an intensive study of the Bible. But the more he immersed himself in Scripture the more he found to support the Catholic faith, and in 1992 he entered the Catholic Church. His conversion story, "A Triumph and a Tragedy," is published in Surprised by Truth. Besides being an author, Jimmy is the Senior Apologist at Catholic Answers, a contributing editor to Catholic Answers Magazine, and a weekly guest on "Catholic Answers Live." View all posts by Jimmy Akin