In addition to public holidays, Danish Law regarding mandatory shop closing (Danish: Lukkelov); mention three additional shop closing days: 5.July, 24.Dec. and 31.Dec. See section Other special days for details.
Other special days
Some of these days derive from politics, and some from Roman Catholic traditions that predate the current national church. Some are simply the Scandinavian tradition of starting the celebrations of a special day on the evening before the actual day.
References
Public holidays in Denmark Wikipedia(Text) CC BY-SA