Geomagnetic latitude: why Yellowknife can beat Rovaniemi

Two kinds of latitude

Geographic latitude is the angle north of the equator. Geomagnetic latitude is the same angle measured from the magnetic equator, which tilts relative to the geographic one. The auroral oval is organised around the geomagnetic pole, so for aurora the second number is the one that matters.

The geomagnetic pole is not the north magnetic pole that a compass points to. It is the pole of the best-fitting centered dipole in the IGRF model. For 2026 it sits at about 80.9 N, 72.8 W, on the Canadian side of the Arctic. That is roughly 9 degrees from the geographic pole.

The formula

Aurorix converts each place with the spherical formula sin(φm) = sin(φ) sin(φp) + cos(φ) cos(φp) cos(λ − λp), where φ and λ are the place's latitude and longitude and φp and λp are those of the geomagnetic pole. Two checks: the pole itself comes out at 90 degrees, and the geographic north pole comes out at 80.9 degrees, the pole's own latitude.

The result is an approximation. A centered dipole ignores the real field's irregularities. Corrected geomagnetic coordinates, which follow actual field lines, can differ from the dipole value by several degrees in some regions.

What the table shows

The table lists the six destinations ordered by geomagnetic latitude. The "Kp needed" column applies NOAA's rule of thumb: the equatorward edge of the oval is near 66 degrees at Kp 0 and moves about 2 degrees per Kp step. A place needs the first whole Kp at which the edge has reached it.

Reykjavik and Yellowknife come out higher than Abisko or Tromsø despite being 4 to 7 degrees further south geographically. Rovaniemi, in Finland, comes out lowest, with Fairbanks next. That order is the reason a quiet night can be worth it in Iceland or the Northwest Territories, and why Rovaniemi needs a little more activity than the others.

Why not just go as far north as possible

The oval is a band, not a cap. Its poleward edge lies a few degrees above the equatorward one, so a place far inside the polar cap sees aurora toward the south rather than overhead. The destinations on Aurorix are all near the band at quiet times, which is why they are popular.

For a trip, geomagnetic latitude is one input. Clear weather, dark nights and local transport matter as much. See the guides on darkness and cloud cover.

Six places by geomagnetic latitude

Centered-dipole values with the 2026 IGRF pole at 80.9 N, 72.8 W. Sorted from highest to lowest geomagnetic latitude.

Quellen

• IGRF geomagnetic pole positions (WDC Kyoto)
• NOAA SWPC: Tips on viewing the aurora
• NOAA NCEI: IGRF geomagnetic reference field