Statistics at the end of the post.
There is always the question, "How often do you see the Northern Lights?" And it is not super easy to answer, because there are no good and available statistics to work from. Most of what we know is based on observations from different operators that do tours in a very big area or computer-generated data from different services.
Seeing the Northern lights with your eyes, or having a night out that looks good on paper are two different things.
If you could teleport between the north and the south of the county you would have a very big chance of seeing the lights on a more or less daily basis, but that is not the way it works in real life. You take a chance with a starting point close to where you sleep, and then there is a healthy portion of luck, variables like the sun, magnetic field and weather, and the guide's experience. This unscientific overview documents Northern Lights observations made on tours that you can do out of Tromsø, or lights seen in the city of Tromsø.
Some operators claim to have a success rate of more than 91%. I have also been operating on an 8 to 9 out of 10 success rate for years, but I have not made an official statistic to "prove" that that is the case - it has been more a gut feeling. It also wouldn't count the days I stayed home cause of bad weather, unsafe conditions, sick kids, social life, other assignments, etc.
These non scientific "findings" are based on observations made by myself and others in the Tromsø area. A rather big area with an operating range of about 3 hours by car inland and about 2 hours towards the coast. At least that is the traditional range, some operators do go further if necessary. The Kp index data considers the forecasted strength between 6 p.m. and midnight for the given day. A high Kp means more activity but does not necessarily show us northern lights. Let us call a high Kp a higher theoretical chance.
Since one guide can´t be out every day, making a statistic that collects data from every evening of the month means looking into the social media of different operators, checking different websites, and also looking into the blogs of some tour operators that are very active. It could also mean making a few phone calls.
Observed Northern lights
Northern lights are either observed on tour or from other operators in the Tromsø area. This means documented with photos or seen.
No observed Northern lights
No one, as far as I have been able to find at least, has seen or taken photos of the Northern lights in the Tromsø area at the night in question. This does not necessarily mean that there haven´t been any somewhere. This is an uncertain variable in the statistics. If information is available at a later time the statistics will be updated.
A Kp-index of 2 or more would normally give us a theoretical chance of seeing the Northern lights in the Tromsø area as seen in the illustration above. The city of Tromsø is situated more or less right under the northern lights oval, and between the guides in Tromsø even Kp's under 1 means a theoretical chance. The higher the Kp, the further south it is possible to make an observation. A Kp between 2-4 is normal and gives us nice lights at these latitudes. A high Kp does not guarantee Northern lights.
Cancelled due to weather
Some nights are simply unsafe to travel on. Some operators will go anyway, and we still
haven´t had any serious accidents with northern light transports. When the National Weather Service recommends us to stay indoors we normally don´t go, but operators make their own decisions as well based on experience and the need for income. The statistics give an overview of how many days every month tours are canceled due to weather and driving conditions. The data is both from my own decisions and the decisions of the bigger operators in Tromsø.
Northern Lights season
The Northern Lights season lasts from the 15th of September to the 10th of April. It is possible to observe strong lights by the 20th of August, and it can be quite spectacular to get the sunset and the lights in one photo. It is not possible to see the lights during the summer (May - July) due to the Midnight sun.
Northern Lights statistics for 2023/2024
The statistics are updated at the end of each month.
October has been a really good month in the Tromsø area, and operators are happy to take guests out on tour with high chances of getting a very nice experience. All in all, there were only 5 days in October where we couldn´t find any documented observations - this is most likely due to weather and/or low activity. Looking at the graph below we had a success rate of roughly 80%, but only a kp2+ on around 70% of the days. This is positive since it means that we are seeing lights even on days with low activity. November has also started with nice lights - November 5th made it to the national news and was seen as far south as Ireland.
In September we observed NL 50% of the nights, and the Kp-index has been 2+ 70% of the nights based on information from the National Weather Service (YR) and Spaceweather Live. There were no cancelations due to weather or unsafe conditions. This month in 2023 has 2 more nights of observed NL compared to the same month in 2022.
Northern Lights statistics for 2022/2023
The NL observations in 2022/23 are solely made from my own data and a quick go-through of data from social media and blogs online. The average number of nights where the NL has been observed is 13, so about 1/3 of the possible nights in each month. April is a bit unfair to count since it only entails 10 nights where it is still dark enough for NL observations to be made. Most operators stop their tours around April 1st.