# DOI: https://doi.org/10.5880/Kp.0001 # LICENCE: CC BY 4.0, please cite: # Matzka, J., Bronkalla, O., Tornow, K., Elger, K. and Stolle, C., 2021. # Geomagnetic Kp index. V. 1.0. GFZ Data Services, # https://doi.org/10.5880/Kp.0001 # Matzka, J., Stolle, C., Yamazaki, Y., Bronkalla, O. and Morschhauser, A., # 2021. The geomagnetic Kp index and derived indices of geomagnetic activity. # Space Weather, https://doi.org/10.1029/2020SW002641 # The Kp index was introduced by Bartels (1949) and is produced by Geomagnetic # Observatory Niemegk, GFZ German Research Centre for Geosciences. International Quietest Days Most Disturbed Days Month Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 D1 D2 D3 D4 D5 Jan 1934 6 13 5 9 7 17 12 4 10 11 1 2* 23* 29* 14* Feb 1934 14 6 26 23 1 28 7 27 21 3 9 16 17* 18* 10* Mar 1934 14 20 13 21 1 19 12 27 3K 17A 5 7 31 25 22* Apr 1934 18 29 11 13 30 10 23 17 26 28 1 5* 4* 16* 6* May 1934 28 27 16 29 31 15 17 14 7 8 18 3* 2* 11* 12* Jun 1934 26 21 22 2 25 30 3 1 24 13 6* 5* 12* 8* 18* Jul 1934 22 23 28 10 27 26 21 19 20 2 30 3* 31* 4* 5* Aug 1934 24 9 25 20 23 21 16 8 10 11 28 29 27 3 30* Sep 1934 13 10 14 9 15 5 23 18 21 6 25 24 27 2 3* Oct 1934 19 10 11 9 8 29 31 30 3 23 24 25* 26* 15* 13* Nov 1934 22 1 20 30 21 23 2 15 6 26 7 8* 9* 25* 24* Dec 1934 17 16 23 27 13 10 12 9 6 28 4 29 30 25* 31*