The Icelandic Met Office publishes Iceland's main aurora forecast at en.vedur.is, showing predicted aurora activity on a scale of 0 to 9 alongside a cloud cover map. A good night needs two things at once: enough activity on that scale and a clear gap in the cloud above where you are standing. This guide explains the 0 to 9 scale, the cloud map, what the Kp index means, and when to check.
The aurora forecast at a glance
The essentials before you read the map.
| Aurora forecast in Iceland | |
|---|---|
| Official source | Icelandic Met Office, en.vedur.is |
| Activity scale | 0 to 9, where 0 is very little activity and 9 the strongest |
| Cloud map | White is clear sky, green is cloud |
| Also shown | Sunset, darkness, sunrise, and moon times for Reykjavik |
| When to check | In the evening on the night itself |
The 0 to 9 activity scale
The forecast gives a predicted aurora activity level for around midnight on a scale of 0 to 9, where 0 means very little geomagnetic activity and 9 the strongest. The Met Office points out that even grade 2, described as low, can look good, and grade 3, described as moderate, can be striking, so you do not need a high number to see something at Iceland's latitude. Higher grades are less common. Remember that the number describes the strength of the activity, not a guarantee, because you still need dark, clear sky to see any of it.
Cloud cover: the part that usually decides your night
Activity means nothing if cloud is in the way, so the cloud map is the part most locals watch. On the vedur.is map, white marks clear sky and green marks cloud, and you can move the slider to step through the hours. Cloud hides the aurora completely, which is why chasing the lights in Iceland often means driving toward a white gap on the map. Look for a break in the cloud over the area where you plan to stand, during the dark hours, rather than judging the whole country at once.
What the Kp index means
Many international apps quote the Kp index rather than the vedur.is grade. Kp is the global, or planetary, geomagnetic activity index, running from 0 to 9 and drawn from a network of ground magnetometers, updated through the day. Because Iceland sits at a high latitude, close to the Arctic Circle and under the band where auroras appear most often, even a modest reading can be enough, whereas places far to the south need a much higher number for any chance. The vedur.is activity scale and the Kp index both run from 0 to 9 and both describe geomagnetic activity, so the two feel similar, but for Iceland it is simplest to read the official vedur.is forecast.
Darkness, moonlight, and when to check
The vedur.is page also shows the timing of sunset, darkness, sunrise, and the moon for Reykjavik, and both matter. You need real darkness, which is why the aurora cannot be seen during the bright summer nights, and a full moon can wash out a faint display. Check the forecast in the evening on the night itself rather than relying on a figure quoted days ahead, because the cloud forecast in particular keeps changing. Treat any activity number you see as a forecast, not a live report of what is in the sky right now.
Putting it together on the night
Reading the forecast well comes down to lining up three things: a workable activity number, a gap in the cloud over your location, and genuinely dark hours. Get away from town lights so a faint display stands out, dress for standing still in the cold, and give it time, since the lights can come and go over an hour. You can chase clear skies yourself by car or hand the driving to someone who does it nightly; to compare guided options, see our northern lights tours.
Check before you go
For a current read on the sky, check the Aurora Forecast before making northern-lights plans around How to Read the Aurora Forecast in Iceland.
