The church year in the Lutheran church consists of a type of calendar that focuses on certain days, seasons, and commemorations. Its structure draws us to the act of salvation that has been marvelously accomplished through the work of Jesus Christ.
In general, the church year is divided into three main 'Times': The Time of Christmas; The Time of Easter; and The Time of the Church. Within each main 'Time' are the seasons, such as Advent Season and Lenten Season. Within each season are individual Sundays or particular commemorations, such as Second Sunday in Advent, First Sunday in Lent, and Good Friday.
Certain colors are also associated with the seasons and even notable days of the church year. These colors (such as red for Pentecost and white for Christmas) are displayed on the altar, at the pulpit, and on the garments that the pastor wears during those specific times.
This list gives a general sense of where we are in the church year:
The Time of Christmas = end of November to end of February
The Time of Easter = end of February to end of May
The Time of the Church = end of May to end of November
A helpful resource for learning more about the church year is found on this page of the website of The Lutheran Church—Missouri Synod.