Geomagnetic Storms of 1938
54 geomagnetic storms of G1 or more began in 1938: 20 G1, 19 G2, 9 G3, 3 G4, 3 G5. The strongest began April 16, 1938 and reached Kp 9, rank 23 of every storm since 1932.
By month
Every storm of 1938
Times are UT, when the first block at Kp 5 or more began.
| Began (UTC) | Level | Peak Kp | Hours | Highest daily Ap |
|---|---|---|---|---|
| Jan 4, 12:00 | G1 Minor | 5+ | 9 | 27 |
| Jan 8, 03:00 | G1 Minor | 5+ | 3 | 20 |
| Jan 12, 21:00 | G2 Moderate | 6- | 9 | 29 |
| Jan 16, 21:00 | G4 Severe | 8+ | 27 | 120 |
| Jan 18, 15:00 | G1 Minor | 5+ | 9 | 34 |
| Jan 19, 15:00 | G1 Minor | 5 | 3 | 24 |
| Jan 21, 06:00 | G4 Severe | 8+ | 39 | 128 |
| Jan 25, 12:00 | G5 Extreme | 9- | 18 | 107 |
| Jan 31, 18:00 | G2 Moderate | 6 | 6 | 35 |
| Feb 6, 03:00 | G3 Strong | 7- | 18 | 51 |
| Feb 7, 12:00 | G1 Minor | 5 | 3 | 24 |
| Feb 8, 15:00 | G2 Moderate | 6+ | 15 | 37 |
| Feb 10, 03:00 | G2 Moderate | 6 | 6 | 31 |
| Feb 11, 03:00 | G2 Moderate | 6- | 6 | 27 |
| Feb 14, 06:00 | G2 Moderate | 6- | 12 | 39 |
| Mar 1, 18:00 | G1 Minor | 5 | 3 | 28 |
| Mar 5, 12:00 | G2 Moderate | 6- | 15 | 35 |
| Mar 22, 03:00 | G2 Moderate | 6+ | 54 | 52 |
| Mar 26, 00:00 | G2 Moderate | 6+ | 3 | 26 |
| Apr 6, 06:00 | G1 Minor | 5+ | 3 | 22 |
| Apr 13, 12:00 | G3 Strong | 7 | 27 | 60 |
| Apr 16, 03:00 | G5 Extreme | 9 | 21 | 136 |
| Apr 23, 09:00 | G2 Moderate | 6- | 15 | 41 |
| May 4, 03:00 | G3 Strong | 7 | 18 | 44 |
| May 11, 15:00 | G5 Extreme | 9- | 18 | 103 |
| May 12, 21:00 | G3 Strong | 7- | 6 | 76 |
| May 14, 09:00 | G2 Moderate | 6+ | 21 | 40 |
| May 29, 12:00 | G2 Moderate | 6 | 6 | 38 |
| Jun 2, 21:00 | G1 Minor | 5 | 3 | 16 |
| Jun 12, 18:00 | G1 Minor | 5+ | 15 | 31 |
| Jul 4, 12:00 | G2 Moderate | 6 | 12 | 35 |
| Jul 10, 18:00 | G1 Minor | 5+ | 3 | 28 |
| Jul 14, 00:00 | G1 Minor | 5+ | 3 | 19 |
| Jul 15, 06:00 | G3 Strong | 7 | 39 | 67 |
| Jul 30, 03:00 | G2 Moderate | 6 | 12 | 45 |
| Aug 2, 03:00 | G2 Moderate | 6 | 3 | 27 |
| Aug 3, 21:00 | G3 Strong | 7+ | 33 | 50 |
| Aug 11, 09:00 | G2 Moderate | 6 | 9 | 39 |
| Aug 22, 12:00 | G1 Minor | 5 | 3 | 18 |
| Aug 23, 09:00 | G2 Moderate | 6 | 6 | 28 |
| Sep 13, 18:00 | G3 Strong | 7+ | 51 | 100 |
| Sep 26, 06:00 | G1 Minor | 5+ | 15 | 38 |
| Sep 27, 21:00 | G4 Severe | 8- | 12 | 56 |
| Sep 30, 18:00 | G3 Strong | 7+ | 12 | 45 |
| Oct 7, 12:00 | G3 Strong | 7 | 24 | 67 |
| Oct 25, 00:00 | G1 Minor | 5+ | 3 | 34 |
| Oct 26, 12:00 | G1 Minor | 5 | 21 | 33 |
| Nov 9, 00:00 | G1 Minor | 5 | 3 | 33 |
| Nov 9, 15:00 | G1 Minor | 5 | 3 | 33 |
| Nov 17, 12:00 | G1 Minor | 5 | 6 | 24 |
| Dec 2, 21:00 | G1 Minor | 5 | 6 | 28 |
| Dec 10, 15:00 | G2 Moderate | 6- | 6 | 29 |
| Dec 16, 18:00 | G1 Minor | 5+ | 9 | 30 |
| Dec 18, 12:00 | G2 Moderate | 6- | 6 | 36 |
More
Sources
Kp and ap from GFZ Helmholtz Centre for Geosciences, Geomagnetic Observatory Niemegk, licensed CC BY 4.0: Matzka, J., Stolle, C., Yamazaki, Y., Bronkalla, O. and Morschhauser, A., 2021, The geomagnetic Kp index and derived indices of geomagnetic activity, Space Weather, doi:10.1029/2020SW002641; data doi:10.5880/Kp.0001. Storms, levels and aurora reach worked out by WeatherOverTime from those values and NOAA’s space weather scales. Definitive through August 31, 2026; later values are preliminary. Rebuilt 2026-09-24.