These are called the liturgical seasons . The most important thing about the liturgical seasons is not the way the weather changes, but the way the story of God's salvation is told and the way it is celebrated in ritual. Through the seasons of the liturgical year, we look at God's work in the life of Jesus and in our own lives in many different ways. Season by season, year by year, we continue to marvel at what God has done for us. We continue to be dazzled and amazed at how God has brought redemption to our lives.
Advent is the beginning of the church year.
There may be five or more weeks of Ordinary Time between the Christmas season and Lent. There are about six months of Ordinary Time after the Easter season and before Advent. Fourteenth Sunday, Fifteenth Sunday, and so on. The Triduum begins on the evening of Holy Thursday and continues until the evening of Easter Sunday. This is how we are shaped and formed into God's people.