# 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. Quietest Days Most Disturbed Days Month Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 D1 D2 D3 D4 D5 Jan 1932 22 19 21 18 20 23 5 4 6 17 2 28 27 25 8* Feb 1932 17 28 29 16 27 18 2 1 26 21K 4 3 10 20 12* Mar 1932 26 1 17 27 15 16K 25K 13 20A 19A 30 31 10 28 29 Apr 1932 21 20 11 19K 30 12K 29A 16A 10A 22A 7 2 26 24 23 May 1932 9 20 19 8 18 7K 1A 17A 22A 10A 29 30 4* 16* 25* Jun 1932 15 4 28 3 16 29 30 27 18 17 8 10* 9* 20* 11* Jul 1932 29 3 28 13 14 15 25 2 23 1 6 16 7* 8* 5* Aug 1932 10 20 16 19 24 17 7 18 15 11 28 29 27 30 2 Sep 1932 16 12 17 10 11 15 3 13 4 28 25 24 6 23 8* Oct 1932 14 29 6 26 7K 13 8 28K 12 18K 15 21 23 20 16* Nov 1932 24 9 10 22 11 8 27 23 21 7 16 1 14* 17* 29* Dec 1932 23 21 7 22 24 5 11 12 20 29 14 15 16 17* 8* Jan 1933 10 5 11 21 12 4 13 9 18 3 27 28 15* 26* 23* Feb 1933 17 11 16 13 1 6 18 12 8 3 21 22 24 19 23 Mar 1933 5 7 16 9 6 17 8 15 4 2 20 24 18 23 19 Apr 1933 12 13 11 29 14 5 27K 2A 25A 28A 17 19 21 18 20 May 1933 26 9 12 24 11 20 10 23 8 21 1 31 6 18* 2 Jun 1933 6 24 16 5 11 23 18 4 22 7 13 1 20* 14* 28* Jul 1933 15 7 16 30 13 21 29 14 31 28 24 23* 9* 27* 18* Aug 1933 1 11 3 31 9 4 12 28 10 2 5 6 13 21* 18* Sep 1933 5 6 3 7 24 4 30 26K 1 22K 9 15 13 14 10 Oct 1933 1 3 29 31 30 23 21 28 22 19K 7 5 14 18* 9* Nov 1933 26 17 24 25 14 30 15 16 13 29 8 6 7 11* 4* Dec 1933 30 24 31 23 12 14 15 1 21 16 5 4 10* 9* 3* 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* Jan 1935 6 9 7 8 14 29K 10 16K 5 12K 17 23* 28* 18* 24* Feb 1935 28 27 11 6 5 19 4 9 12 7K 13 14 2 21* 26* Mar 1935 29 28 12 6 10 7 26 5K 23 27K 14 15 13 16* 21* Apr 1935 2 29 28 6 7 1 3 5 22 27 11 12 13 10 9* May 1935 9 8 24 6 7 5 28 23 25 17 1 20* 11* 16* 12* Jun 1935 15 2 3 25 22 24 26 16 1 23 18 8 9 7 10 Jul 1935 17 5 6 3 30 4 18 10 13 20 25 24 8* 14* 22* Aug 1935 14 18 3 17 12 11 4 26 8 13 21* 23* 27* 20* 22* Sep 1935 2 22 21 13 3 6 8 14 20K 5K 11 25 23 17 18 Oct 1935 6 5 3 4 13 9 8 12K 26K 23K 21 24 20 27 22 Nov 1935 10 26 25 4 7 24 23 17 9 15 12 14 30 5* 13* Dec 1935 23 22 6 4 5 21 24K 20 11K 9K 28 15 16* 1* 27* Jan 1936 6 7 4 3 2 16 5 17 1K 20K 26 25 18* 24* 13* Feb 1936 13 28 6 7 12 8 1 5 18 29K 17 16 19 22 21 Mar 1936 3 11 4 12 7 2 13 14 1 30 24 21 23 25* 20* Apr 1936 5 29 6 10 27 26 9 7 30A 28A 21 22 18 19 23 May 1936 24 9 6 8 23 7 3 25 2 5 18 12 19 16 4 Jun 1936 6 23 30 29 28 5 21 25 7 27K 19 9 2 15 10* Jul 1936 23 21 24 1 22 14 26 4 15 27 2 11 6 29 10 Aug 1936 23 7 18 11 24 19 17 16 22 14 30* 10* 8* 6* 1* Sep 1936 16 7 13 19 25 3 20 30 1 14 26* 11* 29* 23* 9* Oct 1936 27 22 2 4 12 3 28 13 30 26 17 31 10 16 24* Nov 1936 13 25 23 24 27 22 1 14 21 2K 29 3 11 18* 15* Dec 1936 19 26 25 24 22 10 9 17 16 15 28 27* 4* 5* 1* Jan 1937 15 1 25 24 23 18 19 26 16 31 10 9* 21* 7* 27* Feb 1937 23 8 26 28A 25A 2K 24A 1A 27A 7A 3 19 9 5* 10* Mar 1937 12 7 8 11 3 19 20 10 4K 21 31 5 27 2 15 Apr 1937 9 10 8 14 16 22 15 5 6 7 28 26 25 24 27 May 1937 20 6 7 8 17 18 12 24 22K 13 5 28 29 27 1* Jun 1937 12 26 19 9 11 3K 23 30 2A 4A 6 27 20 5 13* Jul 1937 29 4 28 8 27 31 3 18 30 2 22 24 14 25 23 Aug 1937 24 16 25 31 30 20 17 13 18 11 22 2 4 27* 3* Sep 1937 29 12 2 20 25 3 8 9 28 7 30 11 10* 14* 24* Oct 1937 20 31 30 17 19 18 21 2A 29A 5A 4 11 10 23 8 Nov 1937 16 15 6 1 4 5 26 3 10 14 30 18 29 22 23 Dec 1937 14 16 15 28 29 17 27 13 5 4 23 19 18 1 20* Jan 1938 11 10 30A 14A 1A 15A 3A 5A 28A 9A 22 17 25 26 21 Feb 1938 19 22 15 20 21K 17 16 18A 24A 5A 6 14 8 9 10 Mar 1938 20 19 18 31 10 16 30 28 9 13 23 22 24 5 26 Apr 1938 5 28 2 29 30 27 1 20 21A 26A 16 14 23 13 6 May 1938 23 20 26 1 7K 19 8 9K 21 31 12 11 4 14 29 Jun 1938 23 15 28 14 20 24 25 19 27 26 12 8 13 2* 11* Jul 1938 28 26 25 27 18 3 24 12 22 7 15 30 16 4 10 Aug 1938 16 15 20 18 19 27 14 9 26 17 4 11 5 23 2 Sep 1938 24 19 6 25 2 1 18 20 4A 21A 15 28 14 27 26 Oct 1938 5 14 31 13 12 15 18 30K 22 17K 7 8 1 25 27 Nov 1938 12 13 11 30 5 3 2 4 7 1K 9 8 17 21 26* Dec 1938 8 1 26 27 31 29 25 24 7 30 18 17 10 3 22 Jan 1939 27 26 4 1 13 30 3 29K 28 2 17* 14* 21* 9* 5* Feb 1939 12 21 22 27 13K 26 8K 20A 14A 23A 25 6 24 7 2 Mar 1939 19 18 7A 25A 13A 14A 20A 24A 10A 26A 29 28 30 4 22 Apr 1939 15 16K 7 6A 30A 26A 14A 13A 27A 8A 17 23 25 24 19 May 1939 14 12 30 31 11K 4A 13A 10A 15A 27A 1 7 2 6 29 Jun 1939 9 7 8 12 25 11 17K 6 10A 24A 14 16 2 29 21 Jul 1939 7 10 9 30 13 8K 31 29 23A 28A 5 20 3 4 26 Aug 1939 3 9 6 2 4 7 31 5 8 15 22 12 23 16 13 Sep 1939 29 1 5 23 28 27K 15 4K 8K 16A 17 3 19 20 9 Oct 1939 27 2 12K 10 25 20 26K 31A 24A 22A 13 15 14 4 17 Nov 1939 22 23 8 10 18 17 16 21 9 11 13 25 14 26* 12* Dec 1939 19 18 31 14 20 4K 17K 26 13 3K 7 8 22 21* 6