The liturgical colour of Ordinary Time is green, and the choice carries the season's meaning: not the violet of preparation or the white of festival, but the colour of growth, for the weeks in which the church grows by simply living. What fills the green Sundays is, above all, reading. The reformed lectionary assigns Ordinary Time a course of continuous reading, working through the gospels in sequence rather than jumping between festal highlights: Matthew, Mark and Luke each anchor one year of the three year Sunday cycle, and the weekday cycle reads still more widely. The effect is that the long green season is when a congregation actually hears the body of the gospels, the parables, the healings, the teaching, most of which belongs to no feast.
The season is not featureless. Saints' days stud it throughout, and its final weeks turn deliberately toward the end of things, the readings darkening toward judgement until the last Sunday, kept since the twentieth century as the feast of Christ the King, closes the year the way a keystone closes an arch; Advent begins the whole cycle again a week later. Ordinary Time is thus the season that carries the calendar's actual weight. The feasts give the year its shape, but the green Sundays give it its length, and most of a lifetime's churchgoing happens inside them.