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
Aug 12
Aug 13
Aug 14
Aug 15
Aug 16
Aug 17
Aug 18
Aug 19
Aug 20
Aug 21
Aug 22
Aug 23
Aug 24
Aug 25
Aug 26
Aug 27
Aug 28
Aug 29
Aug 30
Aug 31
Sep 01
Sep 02
Sep 03
Sep 04
Sep 05
Sep 06
Sep 07