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Northern Lights Forecast

Everything you need for your ultimate Northern Lights experience in the Arctic

How to  forecast the Northern Lights

One of our most frequently asked questions we get is “What is the Northern Lights Forecast?” with so many people traveling from all across the globe to see the Northern Lights, we want guests to be informed about the reality when chasing the green lady in the sky. When looking for a tour operator to see the Northern Lights, it is important to keep a few things in mind.

There is no way to definitely say if the northern light will appear, however there are several factors we can consider.

Recent solar activity – there has to be some activity for the stronger shows to appear. If there are more sunspots or flares than usual, then there is more lightly to be stronger activity. One of our favorite emails to subscribe to is from Space Weather. They send interesting updates about solar flare activities, solar wind, and other extraterrestrial weather conditions that affect the Northern Lights. 

Solar wind speed/Density– Just as normal weather changes, so do the Northern Lights. Though there seems to be several types of Northern Lights, they are all effected by solar wind speed. The faster or more dense solar wind produces different and more spectacular auroras. The faster the solar wind moves, the more movement you can expect to see in the sky, and the denser and brighter the lights can appear. These Northern Lights are the ones that move faster than you can ever dream of. When the solar wind speed is slower, or there is a less dense solar wind, the Northern Lights slowly caress the sky. This is also a spectacular way to experience the lights. 

Current magnetic field alignment or pull – the earth’s magnetic field always has the last say on whether any particles from space are allowed into the atmosphere. Without it, the earth would have lost its atmosphere to the solar wind shortly after the atmosphere formed, much like Mars.

If the Magnetosphere pulls to the south, the gaps in the northern half of the earth open up and allow more activity to flow through, if it pulls to the north, the opposite applies, and the activity “misses us”. This “pull” is fairly random, but can reverse in minutes, allowing some activity through, then closing. It can also stay open for hours, allowing for a full night of aurora although this is very rare.

The time of the day & earth’s alignment this is important as to have the best possible chance of seeing auroras, you need to be on the opposite side of the earth as the sun, as close to solar midnight as possible. In Tromsø, this is between 23:27 and 23:58 (outside daylight saving time). It is not exactly midnight as we are a little east of the centre of our timezone, GMT+2. However we experience the Northern Lights to have a strong activity between 19:00 – 01:00 and have scheduled our tours likewise.

Great weather & clear skies: While all of the “signs” may be on your side, if clouds roll in, there will be a very difficult chance to see the northern lights. With that being said, we check local forecasts and find openings in the clouds when possible. Sometimes we can drive to areas further inland, or through mountain passes ensuring we are reaching a different weather system area.

Northern Lights Forecast “Talk” 

The Solar Cycle. 

Many people say the sun has a certain heartbeat and every 10-12 years the adrenaline starts pumping because the sun will release a number of sunspots. The strength is measured by the number of sunspots visible on the sun and this is known as the Solar Cycle. The more solar energy that is released into space, the higher chance of aurora activity.

You may be asking yourself “where are we on the solar cycle?” and while the question is relevant, do not postpone your Northern Lights vacation if you read we are at a “low cycle” because 2017 and 2018 were great years for Northern Lights activity, and 2019 is supposed to be one to remember. You may just have to sit out a little longer and wait for them.

KP Index 

When you land in your Northern Lights destination, you may hear a lot of “KP Index Northern Lights” talk when looking for the Northern Lights Forecast. This is because it is one of the most important measurements of the Northern Lights. It has a scale from 0 to 9. The scale is a measure of geomagnetic activity. The higher up you are in latitude, the lower KP index you will need to see the lights. For example, when looking for the Northern Lights forecast in Tromsø, you will need a KP index of 1 to see the Northern Lights. While in Iceland, which is further South, you may need a KP index of 3 to see the Northern Lights.

Geomagnetic Storms

Geomagnetic storms, according to Aurora Service is a period when there is strong to very strong geomagnetic activity due to a lot of build up in Earths “magnetotail”. This causes a lot of particles to go back towards Earth and can make the Northern Lights dance like no one is watching (except we are watching from the Arctic ;)). This table converts the G into Kp.

G1 = Kp5
G2 = Kp6
G3 = Kp7
G4 = Kp8
G5 = Kp9


Key Takeaways:

When planning a northern lights trip, it is important to plan between September and March and to look at the Northern Lights forecast a day or two in advanced. If you have dark, clear skies and are at a high enough longitude the chances of seeing the green lady will be on your side, though there are no guarantees. Some key elements to look at are the KP Index, Solar Storms, Sky clarity and which latitude you are at. A destination like Tromsø is one of the top places in the world to see the aurora.

Tromsø Weather Forecast 

We have search the world and found Tromsø to be the best place to see the Northern Lights!

Northern Lights Tours in The Arctic: 

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