The Aurora Borealis, northern lights, can be seen (if/when tey come on) from middle of August to Early April at this latitude 66 degrees north. Swedish Lapland is one of the best places in the world to experience this cause of quite a few days of clear skies in the Aurora Season and also cause we are an area with very little light pollution. Even lights from a small city takes away the chances to see a normal Aurora.
The solar winds carry charged particles through space that gets sucked in to the globes magnetic field, and if the charge, density and speed of the solar wind is right there are good chances the lights will come on. If there has been a solar storm, making the solar wind stronger, chances for a more intense light are there.