Magnetic latitude
Why some places see the aurora far more often than their position on a map suggests.
The auroral oval is centred on Earth's magnetic pole, not the geographic North Pole. The northern geomagnetic pole, which the oval circles, lies at about 80.8°N, 72.6°W, between Ellesmere Island in the Canadian Arctic and northern Greenland: about 1,000 km from the geographic pole. So what matters for the aurora is your magnetic latitude: how far you are from the magnetic pole, measured in degrees like ordinary latitude.
What this means
- North America is closer to the magnetic pole than Europe at the same map latitude. Edmonton and Hamburg are both at about 53.5°N, but Edmonton's magnetic latitude is about 60° and Hamburg's about 54°. Polar Lights reckons Edmonton needs about Kp 2 for aurora low on the horizon, and Hamburg about Kp 5.
- Siberia and northern Scandinavia are further from the magnetic pole than their latitude suggests, so the oval sits further north there.
- In the south, the geomagnetic pole is offset towards Australia. Hobart, at about 43°S, is at about 50° magnetic latitude, which is why Tasmania and southern New Zealand see the southern lights during strong storms.
How Polar Lights uses it
The Your sky card shows your magnetic latitude (Mag. lat) and, under Needs, the Kp at which aurora is usually seen from your place. Places right under the auroral zone can see aurora even at Kp 0. Further from the pole, every 2° of magnetic latitude adds roughly one point of Kp.
It changes
Earth's magnetic field shifts slowly. The north magnetic pole, where a compass needle points straight down, has moved from northern Canada towards Siberia over the past century; the geomagnetic pole that the oval follows moves much less. Polar Lights works out magnetic latitude from the 2025 International Geomagnetic Reference Field (IGRF), using its dipole: a good approximation for aurora forecasting, though local differences of a degree or so are possible.