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

1

03-06h

0

06-09h

1

09-12h

0

12-15h

1

15-18h

1

18-21h

2

21-00h

2

Tomorrow

00-03h

2

03-06h

1

06-09h

2

09-12h

2

12-15h

1

15-18h

1

18-21h

1

21-00h

1

Day After Tomorrow

00-03h

1

03-06h

2

06-09h

2

09-12h

1

12-15h

2

15-18h

2

18-21h

3

21-00h

3

27 Day Aurora Forecast

Nov 29

3

Nov 30

2

Dec 01

2

Dec 02

2

Dec 03

3

Dec 04

3

Dec 05

3

Dec 06

2

Dec 07

2

Dec 08

2

Dec 09

2

Dec 10

2

Dec 11

2

Dec 12

3

Dec 13

4

Dec 14

3

Dec 15

2

Dec 16

2

Dec 17

3

Dec 18

3

Dec 19

2

Dec 20

2

Dec 21

2

Dec 22

2

Dec 23

2

Dec 24

2

Dec 25

2