The K-index quantifies disturbances in the horizontal component of earth’s magnetic field with an integer in the range 0–9 with 1 being calm and 5 or more indicating a geomagnetic storm. It is derived from the maximum fluctuations of horizontal components observed on a magnetometer during a three-hour interval.

The official planetary Kp-index is derived by calculating a weighted average of K-indices from a network of geomagnetic observatories. Since these observatories do not report their data in real-time, various operations centers around the globe estimate the index based on data available from their local network of observatories. The Kp-index was introduced by Bartels in 1939.

Today

00-03h
2
03-06h
1
06-09h
1
09-12h
1
12-15h
1
15-18h
1
18-21h
2
Clear sky
21-00h
2
Clear sky

Tomorrow

00-03h
2
Clear sky
03-06h
1
Clear sky
06-09h
1
Clear sky
09-12h
1
Clear sky
12-15h
1
Clear sky
15-18h
1
Clear sky
18-21h
2
Clear sky
21-00h
2
Clear sky

Day After Tomorrow

00-03h
2
Clear sky
03-06h
2
Clear sky
06-09h
2
Clear sky
09-12h
2
Clear sky
12-15h
3
Clear sky
15-18h
4
Clear sky
18-21h
3
Clear sky
21-00h
3
Clear sky

27 Day Aurora Forecast

Oct 14
3
Oct 15
3
Oct 16
2
Oct 17
2
Oct 18
2
Oct 19
2
Oct 20
2
Oct 21
4
Oct 22
2
Oct 23
2
Oct 24
5
Oct 25
5
Oct 26
4
Oct 27
3
Oct 28
3
Oct 29
2
Oct 30
2
Oct 31
2
Nov 01
2
Nov 02
2
Nov 03
2
Nov 04
2
Nov 05
2
Nov 06
2
Nov 07
2
Nov 08
2
Nov 09
2