The Northern Lights can certainly be seen with the naked eye. However, no two displays are identical, and the Northern Lights vary significantly in terms of brightness and intensity. Stronger auroral displays are much more vivid to the naked eye, revealing a dazzling spectrum of shapes and colours, while weaker displays are far more subtle and trickier to detect. Modern cameras are much better at capturing colours in the night sky than the human eye, however, which is why the Northern Lights tend to appear more vibrant on photographs than they do to the naked eye.
Below, we tackle some of the other most frequently asked questions about the Northern Lights.
What causes the Northern Lights?
The Northern Lights are the product of electrically charged particles ejected from the sun (known as the solar wind) colliding with gases in the Earth’s atmosphere at very high speeds. Most of these particles are deflected, but some are funnelled towards the poles by the Earth’s magnetic field, where they excite atoms and molecules, primarily oxygen and nitrogen, in the upper atmosphere. It’s this interaction that causes auroras, which are seen in both the northern hemisphere (aurora borealis) and in the southern hemisphere (aurora australis).
Where can you see the Northern Lights?
Northern Lights over Siglufjordur, North Iceland (Image via Visit North Iceland)
The Northern Lights occur in a ring-shaped region known as the auroral oval, between latitudes of roughly 60-75 degrees north. This covers much of Scandinavia and the Nordic countries, including Finland, Sweden, Norway, Iceland and Greenland, as well as the Faroe Islands, the Shetland Islands, northern Canada and Alaska. Stronger displays can be seen further south, including the Baltic countries, Denmark, northern Germany, mainland UK and Ireland.
See also: The best places to see the Northern Lights
Why do the Northern Lights display different colours?
Northern Lights over Gällivare, Swedish Lapland
The Northern Lights are most commonly seen as green, which is produced by charged particles interacting with oxygen atoms and molecules at altitudes of around 100-250 kilometres. At very high latitudes, typically above 250 kilometres, lower concentration oxygen interacts with charged particles to produce red auroras, which are much rarer and associated with intense solar activity. At lower latitudes, around or below 100 kilometres, charged particles react with nitrogen, resulting in pink, purple and blue colours, which also occur with stronger levels of solar activity.
When is the best time to see the Northern Lights?
Northern Lights over Smøla, Norway (Image via Kurt Sivertsen - Visitnorthwest.no)
Although the Northern Lights are active all year round, they’re only visible when it’s sufficiently dark at night, which means they can’t be seen in May, June and July in Scandinavia. Late August until early April is generally the ideal time to see the Northern Lights, while the autumn equinox and spring equinox are often associated with elevated levels of solar activity. The Northern Lights can be seen any time after dark when the skies are clear or partially clear, but activity tends to peak between 10pm and 2am.
See also: The best time to see the Northern Lights: A month-by-month guide
How long do the Northern Lights last?
Northern Lights over Sisimiut, Greenland (Image via Mads Pihl, Visit Greenland)
The Northern Lights can last anywhere from just a few minutes to several hours on any given evening. Sometimes, powerful auroral displays can be seen all night while it’s dark enough, with several peaks and troughs in activity.
What are the different shapes of the Northern Lights?
The Northern Lights in their most spectacular form: an overhead corona
The Northern Lights come in many different forms and their appearance varies significantly depending on the strength of the solar activity and where you’re viewing them from. One of the most common shapes is a large arc stretching across the northern horizon, from which tall, vertical pillars may emerge. More active auroras can be seen as clearly defined swirls and ripples, while weaker auroras can appear as a diffuse, barely perceptible tinge in the night sky. The most spectacular auroras take the form of coronas, which explode directly overhead in a mesmerising, firework-like display of colours.
Can the Northern Lights be forecast?
Northern Lights near Inari, Finnish Lapland
Technology has become increasingly capable of tracking space weather events in real time which can directly impact auroral activity, such as solar flares (intense bursts of radiation from the sun) and coronal mass ejections (significant ejections of plasma mass from the sun). Other important factors such as solar wind speed and density, as well as the strength of the Interplanetary Magnetic Field, are also useful indicators to assess the likelihood of seeing the Northern Lights. However, Northern Lights forecasts are not a precise science, and such models tend to be most accurate only an hour or two (or less) in advance.
What is the Kp index?
Northern Lights over Tromsø, Norway (Image: Yngve Olsen Sæbbe - nordnorge.com)
The Kp index measures the intensity of geomagnetic intensity in the Earth’s atmosphere on a scale of 0-9. Most of the time, Kp levels are between 0 and 2, which means auroral activity is largely restricted to high latitude places close to the Arctic Circle. As a general rule, a higher Kp index means there’s a stronger likelihood of the auroral oval expanding southwards – but the Kp index is just an approximation, and not a particularly accurate predictor of real time auroral activity. It’s worth remembering, however, that in the far north of Scandinavia, it’s perfectly possible to see fantastic Northern Lights displays with relatively low levels of geomagnetic activity.
How does solar maximum affect the Northern Lights?
Northern Lights as seen from Gilleleje, Denmark
Solar maximum marks the peak of the sun’s solar cycle, which lasts roughly 11 years. It’s associated with an elevated number of sunspots and more frequent coronal mass ejections and solar flares, which, in turn, leads to more frequent and intense Northern Lights displays. During solar maximum, heightened solar activity tends to result in the Northern Lights becoming visible much further south than usual on a more regular basis. According to NASA, the solar maximum was reached in October 2024 and is likely to continue throughout 2025.
