Geomagnetic latitude, for 398 cities

Why ordinary latitude misleads you

The aurora forms a ring around the magnetic north pole, not the geographic one. Those are hundreds of kilometres apart: the magnetic pole sits over northern Canada, well off the top of the globe.

So the ring is off-centre. It hangs lower over North America and Europe, and sits further north over Siberia. Two cities the same distance from the equator can therefore have completely different odds.

Edinburgh needs a moderate storm — the kind that arrives several times a year. Moscow needs one of the strongest storms on record. The difference is that Edinburgh is closer to the magnetic pole.

It works the other way too. Yellowknife sits at 62.5° on a map but 67.2° geomagnetically, which is why it needs almost no storm at all and is one of the most reliable aurora spots on Earth.

How to read the table

The higher the geomagnetic latitude, the less of a storm you need. Above roughly 65° the aurora appears on most clear, dark nights. Below about 50° it takes a once-in-years event.

The last column is the minimum Kp — the 0–9 scale for geomagnetic storms — at which the auroral oval reaches that city at all. It still has to be dark, and the sky still has to be clear.

Geomagnetic latitude is computed from each city's coordinates against the geomagnetic dipole. Southern-hemisphere cities are shown as absolute values — the aurora australis behaves identically, just mirrored.