The Gregorian calendar was first introduced in Norway in 1700.
In the calendar, we find marked both public holidays like the National day on May 17th, religious holidays like Christmas and Easter, and flag days.
The religious holidays comprise three days of celebrations: the eve and then a 1st and 2nd celebration day. The eve’s days are not holidays per se, but most people have a shorter working day.
Flag days are dates when the Norwegian state flag is flown by all branches of government and state agencies. Civilians are also encouraged to display the national flag on these days.
The flag is flown on the birthday of a member of the Norwegian Royal House, on some Christian holidays and on the dates of significant events of Norwegian history.
On the National Day of the Sami people on February 6th both state institutions and civilians are encouraged but not required to fly the Sami flag in addition to the Norwegian flag.
In Norway, it is also very common to fly the Norwegian flag on private occasions like birthdays, christenings, confirmations, weddings or an important private celebration.
Flag days are marked on the calendar, so if you are in Norway and you see flags flying in the wind you can just double check with the calendar which occasion it is.