"
But for a growing number of people, taking part
in the holiday means wearing orange. According
to this increasingly popular tradition,
Protestants wear orange and leave green attire
to Catholics. Thus, the color you wear actually
depends on your religious affiliation. While this
color tradition is not well known, it has deep
roots in Irish history..."
http://thefederalist.com/2016/03/17/why-you-should-wear-orange-this-saint-patricks-day/
