When can you photograph the aurora at Tromsø?

At geomagnetic latitude ~67°, Tromsø sits under the auroral oval — the northern lights appear on quiet nights, so the limiting factor is almost never Kp, it is cloud.

What decides a good night here

• Aurora shows even at Kp 0–1; you are inside the oval, not waiting for it to expand to you.
• Season runs late September to late March — outside that the sky never gets dark enough.
• Coastal weather is the real enemy: fronts roll in off the Atlantic and a "Kp 5 alert" means nothing under 100% cloud. Chase the gaps.
• The polar night (late November to mid-January) gives usable darkness almost around the clock.

Honest note: The Milky Way core never rises usefully this far north, so Tromsø is an aurora-and-winter-sky spot, not a summer-galaxy one.

ShootWindow computes all of this hour by hour for Tromsø's exact coordinates — geomagnetic latitude, the NOAA Kp forecast, darkness and cloud — and turns it into concrete windows instead of a raw forecast.