The liturgical year is made up of six seasons:

• Advent – four weeks of preparation before the celebration of Jesus’ birth
• Christmas – recalling the Nativity of Jesus Christ and his manifestation to the peoples of the world
• Lent – a six-week period of penance before Easter
• Sacred Paschal Triduum – the holiest “Three Days” of the Church’s year, where the Christian people recall the suffering, death, and resurrection of Jesus
• Easter – 50 days of joyful celebration of the Lord’s resurrection from the dead and his sending forth of the Holy Spirit
• Ordinary Time – divided into two sections (one span of 4-8 weeks after Christmas Time and another lasting about six months after Easter Time), wherein the faithful consider the fullness of Jesus’ teachings and works among his people

The mystery of Christ, unfolded through the cycle of the year, calls us to live his mystery in our own lives. This call is best illustrated in the lives of Mary and the Saints, celebrated by the Church throughout the year. There is no tension between the mystery of Christ and the celebration of the saints, but rather a marvelous harmony. The Blessed Virgin Mary is joined by an inseparable bond to the saving work of her Son, and the feasts of all the Saints proclaim the wonderful works of Christ in his servants and offer the faithful fitting examples for their imitation.In the feasts of the Saints the Paschal Mystery of Christ is proclaimed and renewed.

Seasons, saints, and celebrations during the liturgical year are laid out in a yearly liturgical calendar.

source: http://www.usccb.org/prayer-and-worship/liturgical-year/index.cfm