The KP number indicates how far south the aurora might be visible. KP-1 indicates low activity. It might be possible to see the aurora from locations as far south as Mo I Rana (no), Jokkmokk (se) and Rovaniemi (fi).

What causes the aurora borealis?
The aurora borealis are the result of collisions between particles in the Earth's atmosphere and charged particles released from the sun's atmosphere. When this happens we can see the beautiful colors appearing in the sky. The aurora may appear in every color range, but the most common color is green. Aurora borealis is also known as the northern lights.

What are KP numbers and what do they mean?
Well to put it simply-the abbreviation KP comes from the German "Planetarische Kennziffer" which translates to planetary numbers. In English- Planetary Index. So basically- KP-index is a mix of terminology indicating your chances of witnessing the Aurora Borealis.

It's a rising numerical function that is used to calculate and indicate the chances of conditions which are conducive to aurora borealis occurring. The higher the number- the higher the chances of you getting to see some northern lights.

The KP number is a system of measuring aurora strength. It goes from 0 to 9 (0 being very weak, 9 being a major geomagnetic storm with strong auroras visible).

So when you're looking at the aurora forecast page, you want to look for high Kp numbers. The higher the better. Anything above (and including) Kp5 is classed as a geomagnetic storm.

What about the forecast for the upcoming hour?
The following graphics shows the aurora borealis forecast 1 hour ahead in time. The graphics are provided by the Kjell Henriksen Observatory and produced with software called Svaltrak II. The picture shows the location and size of the hit-zone of the electrical particles that hit the atmosphere. The green field is called is called the auroral oval. We must be near, or under this oval to see the northern lights.