From the middle of August, it is dark enough for night photography here in the southern parts of Norway. The milky way season lasts to approximately December this far north. I try to head out as often as I can when there is no moon and the forecast predicts a clear sky.
It is always a delight to see the milky way in-camera, but bringing it out in post can often be challenging. One of the key challenges is that the night sky requires quite a different approach than the ground.
When it is very dark I prefer to shoot a few extra very long exposures for the ground to make sure I have enough shadow detail to work with.