The Anglican Church observes the traditional Christian calendar. The season of Advent, during which we prepare for Christmas, begins on the Sunday closest to November 30. Christmas itself lasts twelve days, after which we celebrate the feast of the Epiphany (January 6).
Lent, the forty days of preparation for Easter, begins on Ash Wednesday. Easter season lasts fifty days, concluding on the feast of Pentecost.
During these times the Bible readings are chosen for their appropriateness to the season. During the rest of the year - the season after Epiphany and the long season after Pentecost (except for a few special Sundays) - the New Testament is read sequentially from Sunday to Sunday. The Old Testament lesson corresponds in theme with one of the New Testament readings.