The pre-eminent question for most people embarking on a Northern Lights Holiday.
The answer to this is driven by a number of factors –
The sun spot or solar flare activity on the surface of the sun, which generates the radiation that ultimately creates the Northern Lights, is the single biggest factor. As we know the sun shines every day and therefore there is a constant stream of energy heading our way. This is measured by a KP index and the intensity of this will dictate the magnitude of the Northern Lights. So there are always Northern Lights overhead somewhere in the world, but at times of a lower KP index this can result in sightings only within the Arctic Circle, (or greater than 66 degrees north).
Weather is the single biggest factor as the Northern Lights are generally only seen in Winter in the extreme climate areas of the Arctic region. As such it is worth researching areas that have generally more stable weather patterns. From experience coastal regions can be affected more frequently by storm fronts so this can affect some places more than others.
Topology – It would appear that the environment you are in plays a big part in your chances of seeing them. Some examples of this would be Abisko in Sweden where the mountain range funnels weather fronts away and results in a lower cloud/ lower precipitation climate and therefore more sightings than on average. Monitoring over many years the average chance of seeing the Northern Lights over a 4 night trip to Abisko is around 83%. Other places that stand out are the frozen Lulea Archipelago where the large expanse of frozen seas results in a much more stable cloud pattern. Along the same lines in and around some of the glacier areas in Iceland such as the area near Hotel Ranga where pockets of clear skies can appear overhead even when weather along the coast can be more variable, or in North Iceland in the Myvatn area. You need clear skies to see the Northern Lights.
Any question about the chances of seeing the aurora needs to cover off the type of aurora you are likely to see. The internet has millions of images of the Northern Lights all giving slightly different impressions of what you can expect to see. To a degree they are linked to the intensity of the KP index, but it’s worth setting in your mind the likelihood of seeing various types:
Probably the most common Northern Lights sighting and visible at a low KP index. This tends to light up the sky, appear quite static and do not take much form. Colours can range from a milky white through to mid shades of green.
This is generally the most spectacular Northern Lights displays as the sky can be perceived to be exploding from a central core. These can be single or multi coloured and are the rarest type of aurora showing.
Rising Vapour Column
This is a very pronounced aurora that seems to rise like a column of smoke and seems to have a touch point on earth. This is but an optical illusion as this dancing show is taking place between 100 -300 kilometres above the earth’s surface.
As you move up the aurora KP scale you are more likely to see a rayed arc. This aurora takes the form of long vertical stripes which move and create an auroral curtain.