01 of 05
What are the Northern Lights?
The northern lights in Denmark are one of the "big three natural phenomena," created by our sun's magnetic activity. The northern lights are caused by large numbers of electrons that stream toward the Earth along a magnetic field and collide with air particles in our sky. The air then lights up rather like what happens in a fluorescent light tube, and what we see is the northern lights, also called Aurora Borealis.
The resulting colors of the northern lights reflect gasses we find up there. The charged particles originate from the sun, and weather conditions on the sun and earth decide whether or not we will see this phenomenon. You can also take certain steps to optimize your chances. It's most common to see shades of green in the northern lights. Red northern lights are rare but you can enjoy them too.
Scientific Explanation of the Northern Lights
Here is a more scientific explanation of the northern lights:
The northern lights are created with sufficient geomagnetic activity and form at... around 60 miles high (around 100 kilometers) above the earth's surface. This makes the lights visible up to 260 miles (400 kilometers) away (on the horizon, due to the earth's curvature). During high geomagnetic activity, the northern lights show when electrons hit air particles, causing them to light up.Continue to 2 of 5 below.
02 of 05
Where to See the Northern Lights
Where can you see the northern lights? You can enjoy them in several locations in the north, but there are few spots as perfect for seeing the northern lights as Tromsø, Norway (near the North Cape), and Reykjavik, Iceland.
Even at the minimal level of northern lights activity, Tromsø and Reykjavik are prime locations to see the northern lights. Out of all Nordic destinations, these places provide you with an optimal chance of seeing the famous phenomenon. In addition, both destinations provide a long, dark viewing season since they are located beyond the Arctic Circle (especially during polar nights, when there is no sunlight).
If you don't want to go that far north, the next-best location to see the northern lights is the region between the Finnish town Rovaniemi and the Norwegian town Bodø, just along the edge of the arctic circle. From here, you can still see the northern lights on a regular basis.
Locations as far south as Umeå, Sweden, and Trondheim, Norway, are not as reliable but... a good alternative for the average traveler. These places require only slightly stronger northern lights geomagnetic activity to enjoy the natural phenomenon up close, so you won't see them as often.Continue to 3 of 5 below.
03 of 05
When to See the Northern Lights
When is the best time to see the northern lights? It's those cold, clear winter nights that provide the highest likelihood of seeing them.
The best time to see the northern lights from anywhere around or above the Arctic Circle (which lies near the towns of Rovaniemi and Bodø) is anytime between September and late April. You'll experience long winter nights here.
Farther south, the season of the northern lights is shorter, partly because there is more light in the months before and after winter. Between mid-October and March is the best time to see the northern lights in that region.
The optimal time of night for the northern lights is 11 p.m. to 2 a.m. Keep in mind that most visitors head out to begin their watch around 10 p.m. and conclude their night around 4 a.m. since the northern lights can be hard to predict (just like the weather in Scandinavia).
Don't forget to learn about photographing the northern lights if you're planning to bring your camera.
If you do not see the northern... lights as expected even if the timing is right, locals recommend to simply wait for one to two hours. Nature tends to reward the most patient.Continue to 4 of 5 below.
04 of 05
Current Forecast of the Northern Lights
To forecast the northern lights, you need to know the location where you will be watching them. The forecast of the northern lights measures the expected geomagnetic activity on the so-called Kp index (1 to 10).
As such, forecasting the northern lights' visibility during your visit depends largely on the forecast of that index number.
Here are some tips to help your forecast:
1. Check your travel dates in the official NOAA Space Weather Outlook, which is always predicted for the next 27 days.
2. Get the Kp number listed for the date you're interested in. The higher the Kp value in the forecast is, the farther south the northern lights will be visible.
3. Make a note of the number and read on to find out how high this number must be a good prediction of the northern lights.
Note: While activity is forecast year-round, the northern lights generally cannot be seen May through September.Continue to 5 of 5 below.
05 of 05
Predict the Northern Lights for a Location
To predict the northern lights at a certain location, you need the all-important Kp number (1 to 10). You need a minimum Kp value, based on different locations.
Northern lights predictions for locations like Tromsø and Reykjavik show the northern lights on the horizon even at 0 Kp from autumn to spring. At least 1 to 2 Kp (and higher) will guarantee that the northern lights are directly overhead at these locations.
Rovaniemi, Finland, also only needs a Kp index of 1 for visibility of the northern lights on the northern horizon.
As far south as Umeå and Trondheim, you'll need at least 2 Kp to predict seeing the lights on the horizon, or a Kp value of 4 to enjoy them overhead.
And when you are down in areas around the Scandinavian capitals Oslo, Stockholm, and Helsinki, the Kp index has to be at least 4 for northern lights visibility on the northern horizon or 6 for the northern lights to take place directly overhead.
In comparison, central Europe requires 8 to 9 Kp (very high auroral... activity) to see the northern lights at all.
Note that the visibility of the northern lights also depends on local weather conditions. Cloud cover will hide the northern lights even if the prediction points to a likely occurrence.