(The Eternal Year, Helicon, 1964, p. 106)
In most parishes, the liturgy is accompanied by special joyous music and, in many places, by the reading of the Gospel passage in several languages by parish members. The Day of Pentecost: Whitsunday, the feast's official name according to the Book of Common Prayer, also traditionally merits the (unofficial) wearing of specially-colored clothing, probably in imitation of this feast's liturgical color, red. My good friend and colleague, Fr. Leo Joseph, OSF, pastor of St. John's Episcopal Church, Lakeport, CA, has a splendid explanation of the background for this in the latest parish newsletter. It's too good not to pass on to you.
" Tomorrow is Pentecost! It is the day each year when not only the priest and deacon, but all of you are encouraged to wear RED. This also includes the gentlemen of the parish, you must have a red shirt or at least a tie in your wardrobe. So let's show our colors!