Sunday cycles A, B and C, and weekday years I and II

In the Ordinary Form the Sunday readings follow a three-year cycle, Years A, B and C, each built around one of the first three Gospels: Matthew, Mark and Luke. On weekdays in Ordinary Time the first reading follows a two-year cycle, Years I and II, while the weekday Gospels are the same every year. Both cycles turn over on the First Sunday of Advent, when the Church’s year begins.

Today the Church is in Year A on Sundays and Year II on weekdays. The next cycle begins on the First Sunday of Advent, 29 November 2026.

Why three years

For centuries the Roman Missal gave each Sunday one Epistle and one Gospel, read every year on that Sunday. The 1962 Missal still works this way, so its column on this site repeats from year to year. The Second Vatican Council asked for the Bible to be opened more generously at Mass, so that over a fixed number of years a much larger part of scripture would be read to the people (Sacrosanctum Concilium, no. 51).

The Lectionary for Mass of 1969, revised in a second edition in 1981, answered that request. It gave Sundays and solemnities three readings instead of two, and spread them over three years so that each of the first three Gospels has a year of its own:

• Year A reads Matthew.
• Year B reads Mark, the shortest Gospel, and fills five Sundays of the summer, the Seventeenth to the Twenty-first in Ordinary Time, with the sixth chapter of John, the discourse on the Bread of Life.
• Year C reads Luke.

John has no year of his own but is read every year: in Lent, through Easter Time, and around Christmas. The Year A Gospels for the Third, Fourth and Fifth Sundays of Lent, the Samaritan woman, the man born blind and the raising of Lazarus, may be read in any year, and are used wherever there are candidates preparing for baptism at Easter.

What is read on a Sunday

A Sunday has a first reading, a responsorial psalm, a second reading and the Gospel. In Ordinary Time the first reading usually comes from the Old Testament and is chosen to echo the Gospel, while the second works steadily through one of the apostolic letters on its own course, so it often has no connection with the other two. In Easter Time the first reading comes from the Acts of the Apostles, and the second follows the cycle too: the First Letter of Peter in Year A, the First Letter of John in Year B and the Book of Revelation in Year C. In Advent, Lent and Easter Time all three readings are chosen to fit the season.

The cycle reaches Holy Week as well. On Palm Sunday the Passion is read from Matthew, Mark or Luke according to the year, while on Good Friday it is always the Passion according to John.

A Saturday evening Mass of the Sunday uses the Sunday’s readings, so the new cycle is first heard on the evening before the First Sunday of Advent. Over the three years, a regular Sunday churchgoer hears a large part of the first three Gospels and a broad selection of the Old Testament, the psalms and the letters.

How to tell which year it is

For this purpose a liturgical year counts as the civil year in which it ends: the year that begins with Advent 2026 and ends in November 2027 counts as 2027. Divide that number by three. If it divides exactly, it is Year C; a remainder of one gives Year A, and a remainder of two gives Year B. For weekdays, an odd-numbered year is Year I and an even-numbered year is Year II. Because one cycle is three years long and the other two, the same pairing of Sunday and weekday year comes round only every six years.

You need not work it out. Every day’s page names the cycle in force, “Sunday Cycle” or “Weekday Year”, beside the rank and season, and each year’s page says which cycle the year opens in and which it turns to at Advent.

Weekday years I and II

The two-year cycle applies only to the weekdays of Ordinary Time, and only to the first reading and its psalm. Year I and Year II each work through their own selection of Old and New Testament books, read more or less continuously from day to day. The weekday Gospel is the same in both years: Mark from the first to the ninth week, Matthew from the tenth to the twenty-first, and Luke from the twenty-second to the end.

The weekdays of Advent, Christmas Time, Lent and Easter Time have a single set of readings, the same every year, so Year I and Year II make no difference there. That is why the change of weekday year at Advent goes unnoticed until January, when Ordinary Time begins after the Baptism of the Lord. The next time that happens in your calendar is 11 January 2027.

Saints’ days follow their rank. A memorial normally keeps the weekday readings. Feasts and solemnities have readings of their own; most are the same every year, but some, mainly the moveable celebrations such as the Holy Trinity and Christ the King, have a set for each of Years A, B and C.

Other cycles on a day page

Day pages also show a “Psalter Week”. That belongs to the Liturgy of the Hours, which spreads the psalms over four weeks; it has nothing to do with the readings at Mass.

The 1962 Missal has no cycles at all: a given Sunday after Pentecost has the same Epistle and Gospel every year. If you follow both Missals, the Ordinary Form column changes from year to year while the 1962 column stays the same. For how the two calendars line up, see the Ordinary Form and 1962 calendars compared, and for how the numbered Sundays are counted, Ordinary Time.