The northern lights are also known as the aurora borealis, meaning light of dawn. It’s said the term was first coined by Galileo in 1623 and is derived from ‘Aurora’, the goddess of the dawn and ‘Boreas’, the northern wind personified.

What are the Northern Lights?

The northern lights and their counterpart in the southern hemisphere appear when highly charged solar wind particles flowing from the sun collide with air molecules in the earth’s atmosphere transferring their energy into light. This occurs around the Polar Regions where those magnetic fields converge. These magnetic fields create auroral ovals around the top and bottom of our planet which move and distort as the earth rotates and solar flare activity increases.

They usually occur between 60 and 75 degrees of latitude, which covers northern parts of Canada, Norway, Sweden, Finland, Alaska and Russia as well as all of Iceland.

Interestingly, the northern and southern lights, or aurora australis, occur simultaneously but the inverse seasons mean they generally aren’t visible at the same time.

The aurora borealis are potentially visible under dark skies from late August to mid-April preferably under a clear, cloudless sky. While they occur year round they are weaker than sunlight and therefore sightings aren’t possible from May to July and for most of August.

• Spring and autumn generally provide more stable weather conditions and milder temperatures plus there is greater aurora activity around the equinoxes.
• November through to February offer the darkest skies and longer evenings for maximum sky-gazing.
• The strongest lights tend to appear between 9pm and 2am, though the best sightings often occur between 11pm and midnight.
• Between 4am and 5pm there is generally too much daylight to see the aurora – exceptions are the darkest months of the year and higher latitudes such Svalbard, where it is dark 24/7 from mid-Nov to end of Jan.

Why is aurora activity stronger around the equinoxes?

Due to the axial tilt, as the earth moves around the sun the angle of our magnetic fields relative to the magnetic field of the solar wind change. During optimum configuration, which occurs during the equinoxes, “magnetic cracks” open up that let solar particles in setting off an auroral storm cycle, which in turn creates a higher probability of northern lights.

The northern lights most commonly occur within the geographic area beneath the auroral oval. It encompasses latitudes between 60 and 75 degrees and takes in Iceland, northern parts of Sweden, Finland, Norway, Russia, Canada and Alaska as well as southern Greenland.

The map graphic shown here is indicative of where the aurora are most visible, but they can appear at lower latitudes. Particularly strong solar storms can result in the lights being seen in Scotland and northern England, though most aurora activity occurs within the oval hence its designation.

However, aurora activity is not consistent and the auroral oval – the appearance of light as a ring around the poles – constantly shifts. Therefore strong aurora in Sweden do not necessarily mean strong aurora in Canada and vice versa. The oval is tracked by space weather stations and is shown in forecast modules (see the ovation map below).

Northern Scandinavia and Iceland offer the most accessible destinations from the UK for viewing the northern lights, but there are recognised locations throughout the zone that offer optimum conditions for sightings. It is important to be away from any sources of artificial light, such as street lighting, whereas you do want to be near open spaces offering big sky viewing.

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Auroral Activity and Forecasts

Aurora forecasts are given for a 3-day period and are constantly updated. Longer term forecasts based on the 27-day solar cycle can be useful, but as with long term weather forecasts, they can change.

Recommended websites:

• Space Weather Prediction Centre, part of NOAA generate an animated ovation map depicting the auroral oval based on current solar wind conditions, which is updated every 30 minutes
• SpaceWeatherLive provides a useful 27-day forecast as well as the standard 3-day forecast
• University of Alaska show a daily aurora forecast showing the KP index for different regions
• Aurora Forecast is a useful resource from our trusted northern lights expert in Iceland, Sævar Helgi Bragason combining 3-day forecasts with cloud coverage.
• The Aurora Sky Station in Abisko, Sweden captures images every 5 minutes from their webcam

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