Northern lights: frequently asked questions
Answers about the aurora, the Kp index, clouds, darkness and when in the year you can see it in Norway.
What are the northern lights?
The northern lights are light in the sky made when charged particles from the sun meet the atmosphere around Earth. Oxygen gives green light, and higher up it can turn red. In Norwegian they are called nordlys.
Are the northern lights out tonight?
See the front page: it shows tonight’s aurora chance across Norway, with the Kp forecast, cloud cover and darkness. Choose a place to see the chance there, hour by hour. The figures update every half hour.
What is the difference between the northern lights and the aurora borealis?
There is none. Aurora borealis is the Latin name and northern lights the English one; in Norwegian it is nordlys. In the southern hemisphere the same light is called the southern lights, or aurora australis.
Why are the northern lights green?
The green comes from oxygen about 100 to 250 km up. Higher up, oxygen can glow red, and nitrogen gives blue and purple, often along the lower edge of a strong display. A camera picks up the colours better than the eye.
When in the year can I see the northern lights in Norway?
The season runs from September to April, because the aurora needs dark nights. October to March is best, when it is darkest. In the north there is midnight sun in summer, and then the aurora cannot be seen even if the sun is low.
What is the best month to see the northern lights?
The polar night gives the most dark hours, but around the equinoxes, September–October and February–March, geomagnetic activity is on average a little higher. Those months are therefore especially good, and the nights are milder than in midwinter.
Is this a good year for the northern lights?
The sun runs on a cycle of about eleven years. The last peak came around 2024–2025, and the years after a peak still bring many strong solar storms. The coming winters are therefore good for the aurora, also further south than usual.
What is the Kp index?
The Kp index measures how strong geomagnetic activity is, on a scale from 0 to 9. The higher the number, the further south the aurora reaches. Nordlyskart shows the current value and the forecast from NOAA.
Where in Norway can I see the northern lights?
Tromsø, Alta, Lofoten and Finnmark see the aurora on most clear nights in the season. Further south, such as Trøndelag and eastern Norway, it needs stronger activity, and then it can be seen from Oslo. Choose your municipality to see what applies there.
Can I see the northern lights from Oslo?
Yes, but it is rarer. From Oslo you need roughly Kp 5 to 6, which happens a few times a year. Clear sky and little light from the city help, for example outside the centre.
Can I see the northern lights in Trondheim, Bergen or Stavanger?
Yes, when activity is strong enough. By our calculation you need about Kp 4 in Trondheim, Kp 5 in Bergen and Kp 6 in Stavanger. North of Bodø, Kp 2 to 3 is often enough. Each place page shows the Kp needed right there.
Where can I see the northern lights in Sweden and Finland?
Abisko, Kiruna and Riksgränsen in Sweden and Inari, Saariselkä, Levi and Rovaniemi in Finland lie under the auroral oval and have good chances on clear, dark nights. Nordlyskart shows the chance for every municipality in both countries.
How reliable is the forecast?
The Kp forecast from NOAA covers the next three days and is fairly reliable. The cloud forecast from MET Norway is accurate a few days ahead. The chance we show is an estimate from Kp, cloud cover and darkness. It is not a guarantee, and the aurora can fail to appear even when conditions look good.
How is the chance of northern lights calculated?
Hour by hour through the night: the Kp forecast for that hour against the Kp the place needs, times how much of the sky is clear, and only the hours that are dark. The night’s chance is its best two hours in a row, and we show when they are. Low means unlikely, moderate means it can happen, and high means good conditions. The number is not a measure of how much aurora there will be.
What does proper darkness mean?
We count it as proper darkness when the sun is at least 12 degrees below the horizon, the point called nautical twilight. Then the sky is dark enough for the aurora to show well.
What time is best to look?
The aurora can appear all night, but it is often most active between 22:00 and 02:00. This is not a rule. Look for clear skies and stay out for several hours.
Why do I not see the aurora when Kp is high?
Common reasons are clouds, moonlight, light pollution from towns and streets, or the aurora being low on the northern horizon. Your eyes also need 15 to 20 minutes to adjust to the dark, so turn off your phone screen and look up for a while.
Can you see the northern lights with the naked eye?
Yes. A strong display is clearly green and moves. A faint one can look like a pale, greyish cloud, and a phone photo will often show that it is green. Give your eyes 15 to 20 minutes in the dark.
Does the moon affect the northern lights?
Yes. A full moon brightens the sky, so a faint aurora is harder to see. A strong display still shows well. The trip planner takes the moon phase into account when it ranks the nights.
How do I photograph the northern lights?
Put the camera on a tripod and start at ISO 1600, 10 seconds and f/2.8, with manual focus on infinity. If the aurora moves fast, shorten the exposure. With a phone: night mode, a tripod and the longest time it allows. See the photo guide for a step-by-step recipe.
Does Nordlyskart send alerts?
No. Nordlyskart does not send alerts, but the figures update every half hour. Check the site whenever you like.
Where does the data come from?
The Kp index comes from NOAA Space Weather Prediction Center, clouds from MET Norway, and municipalities and coordinates from Kartverket (CC BY 4.0) and Wikidata (CC0). The map uses OpenFreeMap and OpenStreetMap.