Norwegians are used to contrasts between seasons. The dark arctic winter will surprise you with the complete lack of sun. There will be a few hours of daylight, which can be correctly subscribed as a blue light.
The Auora Borealis
This natural phenomenom can be seen between September and April in the north of Norway. You can often see the northern light between 6pm and 1am, but is often more active betwwen 22 and 23pm.
The northern light appears when the sky is clear and then it's often cold. It changes and waves over the sky in an incredible speed. In the old days the children would be warned against teasing the northern light and you should not wave with a white scarf at it, it would then come closer. Some places had different sayings, that if you greated it, it would wave back to you. At some areas they would keep the children inside when it was occuring, because it could abduct the children.
The northern light is made on the sun and the sunstorm has a eighteen hour travel to come to earth. If you want to learn more about how it's made, have a look at this video https://www.youtube.com/watch?v=3Oy4Mr6c6-0
Experience The Northern Light
To get a best possible view at the northern light, go to a place where you don't get much light pollution. In the north of Norway you will find nice spots to get a good view not far from the city.