How to choose the best night - in a nutshell
We recommend that you chase the Northern Lights as early as possible during your stay. If your plane arrives by 16:00 you will usually have enough time to comfortably make it to the hotel and get ready for our Northern Lights chase that same evening.
Chasing the Northern Lights on your first nights (rather than your last) is a strategy that maximises your chances. For example, if you stay in Tromsø for four nights and join chases on your first and second night, you will still have your third and fourth night to sign up for additional tours and chase again.
Curse and blessing: Weather forecasts
It is a common misconception that it is possible to choose the "best nights" to chase the Northern Lights based on looking at a weather forecast. Here's why:
Weather forecasts are notoriously unreliable
Weather forecasts are a great tool to plan your day, whether you should bring a rain jacket to your dinner in town, an umbrella or if a heavy jacket is the way to go. What they cannot do is accurately predict whether a certain point on the map will encounter rain, snow, fog or clear sky at a specific time of the night. In our years of experience chasing the Northern Lights we have experienced countless nights with the sky clear enough to witness the Aurora in all her beauty, despite the weather forecasts predicting a thick cloud cover from the Norwegian Sea to the Russian border. Those who have chosen to stay home on those nights based on the predictions may have missed the show of their lives. On the other hand, we have also encountered nights that were cloudy despite clear sky predictions.
Whether you check the forecasts weeks, days or hours before the start of the tour, weather forecasts are not a reliable enough source to calculate your chances. We have seen some of the best Northern Lights displays of our careers on the seemingly worst nights. Sometimes a short break in the cloud cover can turn a bleak night into a raging success.
Also, keep in mind that we often travel several hundred kilometers per night in any direction from Tromsø, through coastal climates, microclimates in valleys surrounded by tall mountains and sometimes all the way into Finland. Our experience, teamwork and persistence give us a good chance every night, no matter what the forecast says and no matter what the weather in Tromsø is like.
More curse than blessing: Aurora forecasts
There are countless apps trying to predict the strength of the geomagnetic field every night, tricking tourists into believing that they know how strong the Northern Lights will be. Unfortunately, this is not how it works! The kp-index (which most predictions are based on) measures the intensity of the geomagnetic field. However, given that Tromsø is already in the perfect latitude for the Aurora, we only require a kp-index of 0, the lowest number. While it is true that particularly strong Northern Lights displays are more likely with a high kp-index, we have seen incredible shows on nights with a low kp-index, and we have had nights with a high kp-index and no sign of the Aurora. This leads us to one recommendation: Don't make you decision on which night to chase the Northern Lights based on an app on your phone.
Note: The kp-index is still a useful tool if you want to experience the Northern Lights from locations like Scotland or the Baltics. In those places a high kp-index is a must. The same principle applies if you are in Tasmania or the southern tip of Argentina and want to experience the Southern Lights.
How to actually choose the best night
Generally speaking, the best night to chase the Northern Lights is your first night in town. The earlier you chase, the more time you have during your visit to sign up for additional chases, in case we weren't successful on your first tries.