According to the icelandic met office on the website vedur.is this is all you need to know about when to look for the Norhern lights/Aurora Borealis
“The spectacle of Aurora Borealis requires dark and partly clear skies.
The map of Iceland shows forecast of cloud cover. Green areas are cloudy and white areas clear skies. Move the slider below the cloud cover map, or click directly on a day or time.
The forecast of auroral activity at midnight, scale 0 to 9, is shown in the upper-right box. The scale changes in accordance with the date selected under the cloud cover map.”