Apart from those seasons having their own distinctive character, thirty-three or thirty-four weeks remain in the yearly cycle that do not celebrate a specific aspect of the mystery of Christ. Rather, especially on the Sundays, they are devoted to the mystery of Christ in its fullness. This period is known as Ordinary Time.
Ordinary Time begins on Monday after the Sunday following 6 January and continues until Tuesday before Ash Wednesday inclusive. It begins again on Monday after Pentecost and ends before Evening Prayer I of the First Sunday of Advent.
This is also the reason for the series of liturgical formularies found in both the Missal and The Liturgy of the Hours (Vol. III-IV), for Sundays and weekdays in this season. (GNLYC, 43-44)
As we enter into this ordinary yet nonetheless grace-filled season, let us remember that the greatest part of the green of growth indeed occurs during the long periods of patient waiting. In the seeming emptiness of the ordinary, God comes to make his dwelling with us.