Red means they are a national holiday (banks and schools closed) Green means schools and banks are open, etc.
See Periods of Mourning for information on how it works when someone important passes or something such as a terrorist attack occurs.
January 1: New Years Celebration
February 8: Thomas Abdication Day
February 14: Saint Valentines Day
March 4: Valiant Day
March 17: Saint Patricks Day
Easter Sunday: Easter
May 26: Molossia Day
Sometime in the Summer: Race of the Jackets
August 16: Poop Island Independence Day
September 21: Day of the Monarch
October 31: Halloween
November 1: King Mason Day
November 2: Queen Regent Joia Day
Thanksgiving Day: Thanksgiving
December 25: Christmas
December 31: New Years Eve