The northern lights (and the southern lights) reach much further from the poles than most people think. During a strong storm they can be seen from England, Germany and much of the United States.
The northern lights (and the southern lights) reach much further from the poles than most people think. During a strong storm they can be seen from England, Germany and much of the United States. This lesson is about the practical side: reading the forecast, choosing the time and place, and why your phone often sees more than your eyes. For the physics behind it, see the Space Weather track.
Charged particles from the Sun are guided by Earth's magnetic field towards the polar regions, where they hit the upper atmosphere and make it glow. The glow forms a ring around each magnetic pole, the auroral oval.
The Kp index runs from 0 to 9 and sums up how disturbed Earth's magnetic field is. The higher the Kp, the further from the pole the aurora reaches. Roughly, in the northern hemisphere:
A strong forecast is only half of it. The sky has to cooperate too.
You can only see the aurora in the Arctic.
During strong storms it reaches far further. At Kp 6 to 7 it can be seen from southern England and the central United States.
A high Kp forecast means you will definitely see it.
You also need darkness, clear skies and a view towards the pole. Cloud stops more aurora sightings than anything else.
You now know how to read the Kp index for where you live, when and where to look, and how to photograph what your eyes can barely see. The aurora forecast shows the live Kp, the outlook for the next few days and a verdict for your location.