The Kp Index You Are Checking Comes From Virginia, Germany and Canberra
The number every aurora app shows you is assembled from magnetometers in Virginia, Germany and Australia. Not one of the thirteen observatories behind Kp is inside the Arctic Circle, and the live value uses only eight of them. What that does and does not tell you.
The Northern Lights Equinox Effect Is Real: 1.71×, or 1.41×, Depending on What You Count
The trade says activity roughly doubles at the equinoxes and never says what it measured. On ninety-four years of GFZ data there are two right answers, 1.41x and 1.71x, and the gap between them is the whole story. Plus the reason the bonus does not save September.
Three Nights in Tromsø Is a Coin Flip: How Many Nights You Need to See the Northern Lights
The trade says three nights, and attaches a percentage with no method behind it. On eleven seasons of cloud data three nights in Tromsø is 51.2%, a coin flip on the weather alone. Here is the calculation, and why the obvious version of it is wrong.
You Will Probably See Grey: What the Northern Lights Look Like to the Naked Eye
The world's standard brightness scale for the aurora describes its lowest step as barely visible, about as bright as the Milky Way, with no colour. That step is the common one. Here is what your eye can do with it, and why the trip is still worth taking.
September Is the Worst Month for Northern Lights in Thirteen of the Fourteen Places We Measure
September has the clearest sky of the whole aurora season in six of the fourteen places we measure, and it is still the weakest month of the season in thirteen of them. The reason is not cloud. It is that this far north the darkness has not arrived yet.
The Nights Worth Booking This Northern Lights Season, Destination by Destination
Seven new moons, fourteen destinations and eleven seasons of cloud data on one line. Which weeks of the 2026-27 season are worth booking, where, and why the month you pick matters more than the operator you pick.
The Three Best Aurora Seasons in Thirty-One Years Were All on the Way Down
The sun peaked in October 2024 and the trade has been selling "last chance" ever since. Ranked on the open geomagnetic record, the three most active aurora seasons of the last thirty-one all came after a maximum rather than at one. The ranking, and its window.
Aurora Season 2026-27: What the Numbers Actually Say
The season opens in September. Here is what eleven seasons of cloud data, calculated darkness hours and a sun past its peak say about the months ahead, including the month everyone recommends and probably should not.