Recipe · Aurora
What Kp index do you need to see the aurora where you live?
The single most useful number in aurora chasing is your geomagnetic latitude — your distance from the magnetic pole, not the geographic one. It decides how strong a storm (measured by the planetary Kp index, 0–9) must be before the oval expands over your head:
| Geomagnetic lat | Kp needed | For example |
|---|---|---|
| 66°+ | Kp 0–1 | Tromsø, Fairbanks, Abisko |
| 60–64° | Kp 2–3 | Reykjavik, Anchorage, Yellowknife* |
| 56–58° | Kp 4–5 | Edinburgh, Gothenburg, Tallinn |
| 52–54° | Kp 6–7 | Berlin, Amsterdam, Dublin |
| ≤50° | Kp 8–9 | Central/Southern Europe — major storms only |
*Note how North America's thresholds sit at lower geographic latitudes — the magnetic pole leans toward Canada, which is why Minneapolis sees more aurora than Moscow.
Kp alone isn't a shoot window though. You also need darkness (sun below −12°; forget high-latitude summers) and workable cloud cover — the most common way an aurora night dies. ShootWindow computes your geomagnetic latitude, pulls NOAA's 3-day Kp forecast, and crosses it with the hourly cloud forecast — alerting only when all three align. During solar maximum (now, 2026), mid-latitude windows appear more often than most people think; they're just short and easy to miss.