Kp is a number from 0 to 9 that measures geomagnetic disturbance. It is a global average, lagged three hours, and incomplete. Here is what it actually means in Tromsø — when the sky agrees.
Aurora is technically present overhead at this latitude even at Kp 0 — but faint. Worth a glance from the harbour, not a drive.
Most of the season sits here. Drive 30 minutes from city lights, look north, wait. The sky usually delivers within an hour.
Three or four nights a year. Visible from the city centre. The sky moves fast, colours shift to red. Stay out.