The Aurora Visibility Index (AVI) is calculated using space weather data (KP index, Solar Wind speed, Solar Wind direction) combined with forecast cloud cover and hours away from daylight for each given time / location. The top part of the forecast graph shows the AVI. The higher the AVI measurement, the better chance there is of seeing an aurora. The lower part of the graph is the forecast cloud cover. The higher the forecast cloud cover, the less chance there is of seeing an aurora. The weather in Iceland is constantly changing, and AVI accuracy is dependant upon many uncontrollable variables. As with any predictive system the actual results may vary. Happy aurora hunting!
Sunrise / Sunset data provided by sunrise-sunset.org