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
03-06h
06-09h
09-12h
12-15h
15-18h
18-21h
21-00h
Tomorrow
00-03h
03-06h
06-09h
09-12h
12-15h
15-18h
18-21h
21-00h
Day After Tomorrow
00-03h
03-06h
06-09h
09-12h
12-15h
15-18h
18-21h
21-00h
27 Day Aurora Forecast
Jan 20
Jan 21
Jan 22
Jan 23
Jan 24
Jan 25
Jan 26
Jan 27
Jan 28
Jan 29
Jan 30
Jan 31
Feb 01
Feb 02
Feb 03
Feb 04
Feb 05
Feb 06
Feb 07
Feb 08
Feb 09
Feb 10
Feb 11
Feb 12
Feb 13
Feb 14
Feb 15