Where you can see the northern lights, town by town

How to read the ranking

The Kp to see it is the value at which the southern edge of visibility, as SWPC and the NOAA scale describe it, reaches the town: below it, the aurora stays below your northern horizon. The Kp overhead is the value at which the oval itself, the band where the light is produced, moves over the town; at that point the display can fill the sky and even appear to the south. The gap between the two columns is the range of nights when you would see it low in the north, often more clearly on a phone camera than by eye.

Places are sorted by the first column. Two towns at the same geographic latitude can sit far apart: Seattle and Fargo are both close to 47 degrees north, yet Fargo needs about Kp 5.1 and Seattle about 6.4, because Fargo is closer to the magnetic pole. Across the Atlantic the effect is stronger: Edinburgh, at 56 degrees north, needs Kp 6.4, more than Fargo.

Why a ranking by Kp, and not a map with colored bands

The maps most sites show are the SWPC view lines for a few Kp values, drawn on a continent. They are honest but hard to read for one town, and they hide the step that matters: the line does not move evenly with Kp. Up to Kp 5, SWPC's rule moves the edge of the oval 2 degrees per step; from Kp 6 the NOAA scale's latitudes move 5 degrees per step. A town just south of the Kp 6 line needs a storm three times rarer than one just north of it, which a band on a map does not show. The table gives the exact value so you can compare it with tonight's forecast on the Kp index page.

Using the ranking with tonight's forecast

Read your town's value against the highest Kp forecast for the dark hours of tonight. If the forecast is below the value, there is little point in going out; if it is within one Kp, it is a maybe worth checking again later; if it is above, look at the clouds. The tool at the top of the page does exactly that for any town or ZIP code.

What the ranking leaves out

It is a ranking of geometry, not of experience. Darkness changes with the season and is worst where the aurora is easiest: interior Alaska and Shetland have no astronomical night for weeks around the June solstice. Cloud climate varies just as much, and the monthly tables on each state and city page show it from NASA POWER data. And the ranking assumes a clear view of the northern horizon: from a valley floor or a street lined with buildings, add a point of Kp.

The state and country pages compare the towns of one region and give, for its main town, the darkness and cloud figures by month. City pages do the same for one city and explain what is singular about watching from there. The best places guide picks the spots worth a trip.