FAQ About Aurora

This is really impossible to answer precisely. I estimate that auroras are visible on about 85–90% of the nights in Lapland — but only if the skies are clear.

On those nights, auroras can range from a faint line on the horizon lasting just 5 minutes, to intense displays dancing across the entire sky for hours. Or anything in between!

With regular solar activity, they often appear as an arc (or two) near the northern horizon, typically lasting 15–90 minutes per night. They may shift, ascend in the sky and ripple slightly, but usually don’t explode overhead.

KP index is a planetary geomagnetic index ranging from 0 to 9 that has a 3-hour update period. It shows the degree of disturbance of Earth’s magnetic field, however, this is not the same as the strenght of auroras. Fluctuations in the Earth’s magnetic field, caused by the Solar wind, can have different consequences to the visibility of the auroras, and their latitude. In other words, the KP numbers of indices are not directly correlated to the perceived strenght of the auroras, and we cannot predict from KP index how far south auroras will be seen.

Most importantly – KP index is not calculated with Lapland in mind, or with North in mind in general. It is derived from 13 magnetometer stations around the world, like Wingst in Germany or Kioto in Japan. The closest station to Lapland is situated in Uppsala, Sweden, which is 850 km away from Rovaniemi.

So, KP index is a meaningful index mostly for mid-latitudes, where one does not see auroras very often. During major geomagnetic events, the Kp index usually rises, and the auroral oval expands toward lower geomagnetic latitudes. In such cases there is a correlation between the KP-index and reality.

But things are different in Lapland and in the North. Yes, with high KP indexes we are also more likely to see some good aurora activity, however, this is not really required. Quite often, we can see some nice auroras, even with low indexes of KP1 or KP2. This is because we are very high up in the north latitudes where auroras appera naturally, even if the global auroral activity is low. Magnetometer stations in the south do not sense this “normal” activity very well. We might even have some auroras with KP index zero, but of course, it will mean that auroras were very small that night.

One major problem with the KP index is that it’s just a forecast. It might come true, but also it can be wrong entirely. I remember so many nights with KP6-7 forecasted, but in reality it was zero. Or vice versa. This because our forecasting abilities are not yet capable to predict the accurate timing of the arrival of the strong solar wind, and sometimes these solar wind streams can miss the Earth entirely.

Another problem is that it updates slowly. A small fluctuation in the solar wind might create a short but good show – perhaps even 15-30 minutes long. The 3 hour update window of the KP index might not really notice such events, or react to them much later, when the whole show is already over.

In any case, there are more important things for us to worry about, such as the weather forecast and the timing of the tour’s departure, and arrival to clear skies. I don’t usually care for forecasted indexes – this is for amateurs. Measured indexes might be interesting to look at – evaluating strong and exceptional auroral events, such as geomagnetic storms.

They are mainly the different properties and characteristics of the solar wind. When it is faster and stronger, it creates a better effect on the Earth’s magnetic field, allowing for more energy to enter. Specifically, the Solar wind’s magnetic polarity (known as the Bz value) plays a big role. As a rule of thumb, when it points towards the South, it has a better chance to connect with the Earth’s North-directed magnetic field. This is not always a guarantee for auroras, but still, the expectations grow higher. When the Solar Wind’s magnetic polarity points towards North, the interactions are less strong, but this does not yet mean “no auroras”. The show just might be more sublte, and better visible for the cameras. You can check different solar wind properties at www.spaceweatherlive.com.

During our tour, we go into great detail on how to read and understand these values.

Aurora is visible from mid-August until end-April – when there is night in Lapland. It is not possible to see auroras in summer months (May – early August) because there is daylight around the clock. I organize my tours from September until early April, when there is enough darkness available to have a good chance of seeing the auroras.

Best times to see the auroras are around Equinoxes – September & October, as well as March & early April. This is due to the “Equinox effect”, and it is backed by statistics. However, this changes year-to-year, depending on the solar activity.

Auroras are of course also visible in November, Decemeber, January and February – depending on the weather & aurora activitity. Some years, especially close to Solar maximum, these months can be on par, or even better than Equinox months.

The main issue with aurora visibility is cloudy weather, not the month or how strong the activity is. Even if aurora is going crazy, it doesn’t help if the clouds are are covering the show. It is also important to be outside, hunting and moving, escaping clouds, city lights and other distractions. 

All are excellent locations, however, there are differences. In very general terms, locations that are further north are better. Geographically speaking, Tromso is more north than Rovaniemi, and thus, has a little bit better expectations in regards of auroral activity. However, this is not the full story. Weather plays a huge role, and if it’s cloudy in Tromso and clear in Rovaniemi, the latter wins. Or vice versa. Also, with higher auroral activity the difference in latitude plays a much smaller role – many areas get to experience a good show!

Weather-wise, there are some areas that do have better expectation of clear skies, such as Abisko area in Swedish Lapland. Quite often we make the very long drive from Rovaniemi to Abisko area and back for this very reason. However, I also met people who booked their trip to Abisko and didn’t see the lights there, due to bad weather or, perhaps, lack of effort. There are also other, lesser known areas with local micro-climate in Finnish Lapland that experienced hunters like myself know and visit on the tours.

Rovaniemi, even though more geographically slightly more south than Tromso and Abisko, provides for a good starting point for aurora tours. As a capital of Finnish Lapland, it is well connected with roads, and due to its central location in the region, we can go pretty much any direction that we want to, and reach areas with clear skies, or with more optimal location in regards of aurora activity.

North of Norway, on the other hand, has many fjords and mountains. They are breathtakingly beautiful, but complicate going from A to B. The roads must go around these geographical features, and sometimes driving for 1 hour might only take you 30-50 km away from the previous spot. In the same time, we can cover much more ground, following the nearly straight paths on the plains of Finnish & Swedish Lapland.

So, this is not an easy question to answer as there are many factors invovled. The choice is yours!

Auroras often look stronger in photos because cameras (even on the phones) collect light for several seconds. Our eye sees the sky in real time, and human eyes are not so good at seeing many things at night time anyway.

Aurora activity and its behaviour play big role as well. Sometimes, the aurora is slow – our eyes do not see a lot of movement or colour – cameras see more. This often happens in the very beginning of the night, when aurora is warming up, charging for a dance, or at the end, when it fades out and “pulsates”.

Other times aurora activity is stronger, and auroras move fast. This happens mostly during so-called “auroral substorms” – explosions of energy in our atmosphere, stored in the Earth’s magnetotail. Aurora can dance with colours of green, yellow, pink and even white. This is when our eyes pick up more colours, and our view and cameras view becomes more equal.

Aurora colours happen depending on which gas molecules are excited by solar wind particles, and at what altitude.

Green is usually oxygen, somewhere between 100–250 km above Earth’s surface. Red is also oxygen, but much higher in the atmosphere, below 1000 km. Nitrogen also makes auroras but they are more rare to see. Strong auroral substorms, coming from so-called Coronal Holes on the Sun, are known to create fast-moving pink auroras. They happen when nitrogen is excited in the atmosphere below the oxygen green auroras, at the heights of 70-80 km. These auroras are usually very fast, and very local, due to their low altitude.

Blue or purple auroas happen when nitrogen is excited above the oxygen red auroras, above 1000 km. They can farm very tall pillars in the skies, but are very gentle and less accessible to the naked eye. These lights appear as grey to the naked eyes, but cameras can see these colours well.

No. This is a myth, or a misconception. Cold weather does not create auroras and does not make them stronger. Auroras are caused by charged particles from the Sun interacting with Earth’s magnetic field and gases in the upper atmosphere. They do not care what temperate it is beneath them, close to the ground.

But cold winter nights are often connected with clear sky, because high-pressure often means clear skies and cold night. So, there is a correlation, but only because the cold makes “holes in the clouds”.

Yes, aurora’s perceived visibility by the naked eye can be affected by the moon phase.

During a full moon, the extra ambient light can wash out faint auroras, especially for those seeing them for the first time. Subtle arcs, colors and pulsating auroras are be harder to notice in bright conditions.

However, when auroral activity is moderate to strong, the moon’s brightness is less of an issue.  It can even be a benefit, as a moonlit landscape helps illuminate trees, snow, and foreground details, often resulting in better photos. Scientifically speaking, strong moonlight also excites our eyes better, making them more succeptible to see aurora colours – but only when they are strong.

If you want to play it safe, aim for a new moon or crescent phase. Avoid 4 days before full moon, and 3 after. That way, you’ll get darker skies for visibility, with just enough light for photogenic landscapes.

Yes, you can, but not very well, and not very often. Very bright auroras can be visible even from the city streets, up above in the sky. However, city centre is a nasty place to watch the auroras due to heavy light pollution. Not to forget – Rovaniemi city centre seems to attract clouds and fog, due to its location at the confluence of two rivers. It is like a big valley that likes to attract all the shit in the sky. There are some exceptions, such as Ounasvaara hill. Even though it is close the city centre, it can sometimes stay above the fog and provides as viewing spot with less light polution. However, it is helpess againts the clouds.

In any case, it is a much better idea to be outside in nature, without light pollution and see auroras in their full glory.