http://www.ucc.org/worship/liturgies/liturgical-colors.html
The use of colors to differentiate liturgical seasons became a common practice in the Western church in about the fourth century. At first, usages varied considerably but by the 12th century Pope Innocent III systematized the use of five colors: Violet, White, Black, Red and Green. The Lutheran and Anglican churches that emerged from the Reformation retained the traditional colors but they disappeared entirely (along with most other ritual) from the worship of the Reformed churches. During the 20th century, the ecumenical Liturgical Movement prompted the rediscovery of ancient Christian ritual—including the traditional colors of the Western church. To these have been added Blue and Gold—colors that were used in some Western rites before the 12th century.
Briefly, the colors express emotions and ideas that are associated with each of the seasons of the liturgical year. Violet is the ancient royal color and therefore a symbol of the sovereignty of Christ. Violet is also associated with repentance from sin. White and Gold symbolize the brightness of day. Black is the traditional color of mourning in some cultures. Red evokes the color of blood, and therefore is the color of martyrs and of Christ's death on the Cross. Red also symbolizes fire, and therefore is the color of the Holy Spirit. Green is the color of growth. Blue is the color of the sky and in some rites honors Mary.
Congregations in the United Church of Christ have the freedom to use any combination of colors (or no particular colors) as seems best to them. The use of traditional colors, however, connects us to the wider Body of Christ and provides worship planners with visual aids that mark the transition from one season to another. Colors can be used in altar and pulpit decorations, vestments, banners and tapestries.
Advent
[colored_box bgColor="#bc369a" textColor="#000000"]Advent is a season of spiritual preparation for the celebration of the birth of Christ (Christmas) and looks forward to the future reign of Christ. Eschatological expectation rather than personal penitence is the central theme of the season. Advent is a preparation for rather than a celebration of Christmas, so Advent hymns should be sung instead of Christmas carols. The first Sunday of Advent is not the beginning of the Christmas season. The Christmas celebration begins on Christmas Eve and continues for the next "twelve days of Christmas."Purple is normally Advent's liturgical color, associated both with the sovereignty of Christ and with penitence. Deep Blue is also sometimes used to distinguish the season from Lent. As the color of the night sky, Blue symbolizes Christ who in one ancient Advent song is called the "Dayspring" or source of day. As the color associated with Mary, Blue also reminds us that during Advent the church waits with Mary for the birth of Jesus.[/colored_box]
Christmas and Christmas Season
The Lectionary readings for Christmas and the following twelve days (culminating in the feast of the Epiphany) invite the church to reflect on the Incarnation (or embodiment) of God as a human being: "The Word became a human being and lived among us, and we have seen his glory...." (John 1:14). In Christ, God enters human history and identifies fully with the human condition.The traditional colors of the season are White or Gold, symbolizing joy in the light of day.
Season after Epiphany
The season following Epiphany continues the theme established on Epiphany Day: the spread of the Good News of Christ from its source in the Jewish community to all nations on earth. The Lectionary therefore explores the mission of the church in the world. The theme of this season (along with the sequence of readings from the Gospel) continues in the season after Pentecost, so both seasons together can be called the "Time of the Church." The traditional liturgical color for both seasons, Green, is the color of growth.Lent
The traditions of Lent are derived from the season's origin as a time when the church prepared candidates, or "catechumens," for their baptism into the Body of Christ. It eventually became a season of preparation not only for catechumens but also for the whole congregation. Self-examination, study, fasting, prayer and works of love are disciplines historically associated with Lent. Conversion—literally, the "turning around" or reorientation of our lives towards God—is the theme of Lent. Both as individuals and as a community, we look inward and reflect on our readiness to follow Jesus in his journey towards the cross. The forty days of Lent correspond to the forty-day temptation of Jesus in the wilderness and the forty-year journey of Israel from slavery to a new community.On Ash Wednesday, ashes are placed on the foreheads of the congregation as a symbol that we have come from dust and one day will return to dust. It is one of many Lenten and Easter customs that remind us of our historical connection with Jewish tradition. With this sobering reminder of life's fragility, we begin a spiritual quest that continues until the Easter Vigil, when new members of the church are often baptised and the entire congregation joins in a reaffirmation of baptismal vows. Most of this time of preparation is symbolized by the color Violet, though the season is bracketed by the mourning Black of Ash Wednesday and Good Friday. As an alternative to Violet, some churches have begun to use brown, beige or gray (the colors of rough unbleached cloth like burlap) to reflect the season's mood of penitence and simplicity. The somber colors are a reminder of the unbleached "sackcloth" worn by mourners and penitents in the Jewish tradition.
Holy Week
During Holy Week, the congregation follows the footsteps of Jesus from his entry into Jerusalem (Palm/Passion Sunday) through the Last Supper (Maundy Thursday) to his death on the Cross (Good Friday). Red, the color of blood and therefore of martyrs, is the traditional color for Palm/Passion Sunday and the next three days of Holy Week. On Maundy Thursday, White or Gold symbolizes the church's rejoicing in the sacrament of the Lord's Supper. But at the end of the Maundy Thursday celebration, the mood changes abruptly: all decorations are removed and the Holy Table is stripped bare. The church becomes as empty as a tomb. On Good Friday, either Black or Red is customary—although the use of no color at all is also appropriate. The Red of Holy Week is sometimes a deeper red than the brighter scarlet color associated with Pentecost.Easter and Pentecost
Instead of finding a sealed tomb, the women who had come at dawn on Sunday are surprised by an angel who announces astonishing news: "Jesus has been raised from the dead" (Matt. 28:7). The heavenly messenger invites the mourners to see the empty tomb and then go and tell the disciples that the Crucified One is alive!The season from Easter to Pentecost is also called the Great Fifty Days, a tradition inspired by the Jewish season of fifty days between Passover and Shavuot—the feast celebrating the giving of the Torah to Moses.
The liturgical color for this season is celebratory White or Gold. When the season ends on Pentecost Sunday, White is replaced with Red. This color reminds the congregation of fire—the symbol of the Holy Spirit. On Pentecost the Holy Spirit overpowered the barriers of culture and race. The first Sunday after Pentecost celebrates the Trinity, and the color again is White or Gold.
Season after Pentecost
This longest season of the liturgical year is a continuation of the "Time of the Church" that began on the Sunday after Epiphany. It explores the mission of the church and uses the color of Green, symbolizing growth. During this season, the Lectionary offers two options for readings from Hebrew Scripture: the first, topical option selects readings thematically related to the Epistle or Gospel texts. The second, sequential option reads through an entire book of Hebrew Scripture in sequence.Other Holy Days and observances
Pentecostal Red is also the traditional color for Reformation Day on October 31. White or Gold is the color for All Saints Day on November 1 and is also an alternative to Green on the last Sunday after Pentecost—the feast of the Reign of Christ.During other observances, the tradition is to use Red on commemorations of martyrs and other saints. As the color of the Holy Spirit, it is appropriate for ordinations. The colors of Christmas, White or Gold, are also customary on other feast days that celebrate the Incarnation or Resurrection of Christ (Holy Name, Baptism, Presentation, Annunciation, Visitation, Ascension and Transfiguration). Black for centuries was the traditional color for funerals, but in the past fifty years many liturgical churches have preferred to use White or Gold—the colors of Easter and therefore of Resurrection hope.