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.

EXTENDED NORTHERN LIGHTS FORECAST

Today

00-03h

4

03-06h

5.33

06-09h

2.33

09-12h

3.33

12-15h

2.67

15-18h

4.67

18-21h

2.67

21-00h

1.67

Tomorrow

00-03h

3.33

03-06h

3.67

06-09h

3

09-12h

3

12-15h

2.33

15-18h

2

18-21h

2

21-00h

1.67

Day After Tomorrow

00-03h

2.33

03-06h

2.67

06-09h

2

09-12h

2.33

12-15h

2.33

15-18h

2

18-21h

2

21-00h

1.67

27 Day Aurora Forecast

Oct 05

5

Oct 06

4

Oct 07

3

Oct 08

3

Oct 09

2

Oct 10

2

Oct 11

3

Oct 12

3

Oct 13

3

Oct 14

3

Oct 15

2

Oct 16

2

Oct 17

2

Oct 18

2

Oct 19

2

Oct 20

2

Oct 21

5

Oct 22

5

Oct 23

4

Oct 24

3

Oct 25

2

Oct 26

2

Oct 27

2

Oct 28

2

Oct 29

2

Oct 30

2

Oct 31

5