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

Tomorrow

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

Day After Tomorrow

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

27 Day Aurora Forecast

Mar 25
4
Mar 26
3
Mar 27
4
Mar 28
4
Mar 29
3
Mar 30
3
Mar 31
2
Apr 01
2
Apr 02
3
Apr 03
3
Apr 04
2
Apr 05
2
Apr 06
2
Apr 07
2
Apr 08
2
Apr 09
2
Apr 10
2
Apr 11
2
Apr 12
4
Apr 13
3
Apr 14
2
Apr 15
2
Apr 16
2
Apr 17
2
Apr 18
2
Apr 19
2
Apr 20
2