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
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

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
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

27 Day Aurora Forecast

Jan 20
4
Jan 21
4
Jan 22
3
Jan 23
2
Jan 24
2
Jan 25
2
Jan 26
2
Jan 27
2
Jan 28
2
Jan 29
2
Jan 30
2
Jan 31
2
Feb 01
3
Feb 02
3
Feb 03
3
Feb 04
3
Feb 05
3
Feb 06
2
Feb 07
2
Feb 08
2
Feb 09
2
Feb 10
2
Feb 11
2
Feb 12
2
Feb 13
2
Feb 14
2
Feb 15
2