The northern lights are a fickle beast – often taking even the most avid hunters by surprise with their appearance and/or intensity. However, there are certain conditions that you need in order to be able to see them at all. Crucial factors are a good KP index score along with dark, preferably clear skies.
The KP index measures geomagnetic activity, and is arguably the most important factor for seeing the northern lights. The index shows the most likely time that you can spot the aurora borealis in Iceland and how strong they will appear to the eye. The higher the KP index score, the better your chances of seeing lights, and the more likely you are to see the pink and purple colors, alongside the green, light up the sky.
Dark, clear skies are also important for seeing the lights. A full moon can significantly brighten the sky, making it more difficult to enjoy the show, so it’s ideal if the moon is smaller on the night you want to go looking.
Heading away from light pollution will maximize your chances of a glimpse, although the very brightest aurora can be seen from cities and even through thin clouds.
The time of night can also have an impact on how easy it is to see the aurora in Iceland. Generally, 9pm until 2am is considered northern lights peak time. The lights also tend to get more visible as the night goes on, so the show can be a long but extremely rewarding one.
If you need your beauty sleep, you'll find that many hotels offer an aurora alarm service, calling your room to wake you if there are hints of color in the sky – so that might help you decide where to stay in Iceland to see the northern lights.
Iceland's northern lights forecast
The Icelandic Met Office provides a northern lights forecast with predictions for the next three days. The map shows cloud coverage over Iceland, and there is a numbered KP index scale in the top right corner that shows the level of solar activity. The scale ranges from 0 to 9 (very low to very strong).
The interactive tool allows you to easily view the northern lights forecast for Reykjavík or any other part of Iceland. However, it’s important to bear in mind that the aurora forecast can fluctuate throughout the day. For the most reliable reading, we’d suggest checking Iceland’s aurora borealis forecast at around 6pm.
If you want up-to-date readings on the go, we’d also recommend downloading the Aurora Forecast app. It shows the position of the auroral oval around the Arctic Circle and features a probability indicator so you can predict how likely it is that you’ll see the lights where you are.