United States

Alaska has the best-placed aurora town in this catalogue and it is not the one furthest north. Fairbanks sits at 64°50′N, south of Rovaniemi and well south of Tromsø, and gets more overhead aurora than either, because the auroral oval is a ring around the geomagnetic pole off northwest Greenland rather than around the geographic one. That offset pulls the ring south over North America.

The second advantage is the one that decides trips. Across eleven seasons of reanalysis, Fairbanks gets a usable sky on 48.9% of season nights: the highest of the fourteen destinations on this site. Its worst month beats the best month of Tromsø, Reykjavík, Alta, Bodø, Akureyri, Saariselkä and Abisko. This is continental interior air, dried by the Alaska Range, and it behaves nothing like a coast.

It also inverts the calendar. Fairbanks peaks at 58.1% in January and 53.0% in February, against 44.0% in September. In Scandinavia the equinox months are the good ones and midwinter is the trap; here the deep cold is the season, and the coldest weeks are the clearest. If you have read that you should avoid December and January, that advice was written about somewhere else.

Which explains the shape of the American catalogue. Nineteen of these 44 departures are built around a heated building: ten lodges and glass cabins on hilltops, six nights at a hot spring, three ice-fishing huts with the sky through the window. Finland competes on how far a van will drive and Iceland on how easy it is to get there. Alaska competes on whether you will still be outside at half past midnight, because at minus 35 in the best month of the year, that is the question.