According to Catholic tradition the colour for the season of Advent is violet.

(I thought about learning more about Advent as I opened the first window on my Advent calendar this morning. Seemingly violet came into use for this season at the end of the thirteenth century. During this time ministers wear violet vestments (clothing worn by ministers). The colours used in some vestments are changed during the year to indicate the seasons of the church year. Obviously violet wasn’t quite so girly in the thirteenth century.)