Solario shows the forecast and the actual state of Earth’s geomagnetic field using the Kp-index. The index quantifies disturbances of the geomagnetic field with a value in the range 0–9 with 0 being calm and 5 or more indicating a geomagnetic storm.

The principal users affected by geomagnetic storms are the electrical power grid, spacecraft operations, users of radio signals that reflect off of or pass through the ionosphere, and observers of the aurora.