Northern lights in September?

Hi Lunebleu,

To see either of the aurorae you need to have two things going in your favour. The first, and most important is an appropriate latitude. The auroral zones are very close to (but not directly overhead) the north and south poles so they are very much over the Arctic and Antarctic Circles - but the aurorae are visible much further away from the poles, appearing lower and lower in the sky the further you get.

Tromso would not be a problem because Norway is suitably placed with northern latitudes and Tromso is way up the top, almost into the auroral zone. It's an ideal place for viewing aurorae. Hence, location isn't an issue, assuming you have an unimpeded view to the north and there's a dark sky (i.e. not near city lights, full moon etc).

The bigger issue for most people will be timing. Unless you're close enough to the zone, an aurora does not appear every night of the year, and not even every week. The glow is caused by the solar wind delivering charged particles that react with our atmosphere, causing ionization near the magnetic poles. This flow varies during the year, so the more particles, the more intense and visible is the aurora.

But Tromso is so well placed that you should see the aurora at least once every two or three nights, regardless of the month of the year, assuming clear sky. Your greatest obstacle is not celestial; it's something much closer to home: clouds.