While the days of various public holidays and observances in Denmark changes each year, the events themselves remain the same.
Below is a link to a website where you can see the exact dates of all of Denmark's national holidays as well as other observances, seasonal dates, and when Daylight Savings Time takes effect this year.
On public holidays, the municipality offices and most, if not all, shops are closed. On observance days, closing times will depend on the office or shop.