Geomagnetic Storms of 1946
60 geomagnetic storms of G1 or more began in 1946: 27 G1, 15 G2, 10 G3, 2 G4, 6 G5. The strongest began September 21, 1946 and reached Kp 9, rank 10 of every storm since 1932.
By month
Every storm of 1946
Times are UT, when the first block at Kp 5 or more began.
| Began (UTC) | Level | Peak Kp | Hours | Highest daily Ap |
|---|---|---|---|---|
| Jan 3, 09:00 | G3 Strong | 7 | 36 | 70 |
| Jan 11, 03:00 | G1 Minor | 5+ | 3 | 23 |
| Jan 23, 21:00 | G1 Minor | 5 | 3 | 16 |
| Jan 24, 12:00 | G1 Minor | 5 | 3 | 30 |
| Feb 7, 09:00 | G5 Extreme | 9- | 33 | 127 |
| Feb 10, 06:00 | G1 Minor | 5+ | 3 | 20 |
| Feb 14, 06:00 | G2 Moderate | 6 | 24 | 33 |
| Feb 19, 18:00 | G1 Minor | 5 | 6 | 27 |
| Feb 20, 21:00 | G2 Moderate | 6 | 21 | 51 |
| Mar 1, 03:00 | G2 Moderate | 6- | 6 | 28 |
| Mar 4, 21:00 | G1 Minor | 5+ | 3 | 25 |
| Mar 10, 00:00 | G2 Moderate | 6+ | 27 | 64 |
| Mar 22, 06:00 | G2 Moderate | 6- | 6 | 27 |
| Mar 23, 21:00 | G5 Extreme | 9- | 78 | 195 |
| Mar 27, 21:00 | G5 Extreme | 9- | 39 | 213 |
| Apr 1, 00:00 | G1 Minor | 5 | 3 | 19 |
| Apr 9, 09:00 | G2 Moderate | 6 | 9 | 36 |
| Apr 14, 12:00 | G3 Strong | 7- | 33 | 61 |
| Apr 23, 06:00 | G5 Extreme | 9- | 36 | 117 |
| May 6, 03:00 | G2 Moderate | 6 | 6 | 41 |
| May 6, 21:00 | G3 Strong | 7- | 12 | 41 |
| May 8, 03:00 | G2 Moderate | 6+ | 6 | 34 |
| May 9, 12:00 | G2 Moderate | 6 | 9 | 49 |
| May 11, 06:00 | G3 Strong | 7- | 9 | 41 |
| May 20, 21:00 | G1 Minor | 5 | 3 | 11 |
| May 21, 18:00 | G2 Moderate | 6+ | 33 | 49 |
| May 23, 15:00 | G2 Moderate | 6- | 6 | 38 |
| Jun 7, 09:00 | G3 Strong | 7+ | 9 | 47 |
| Jun 8, 12:00 | G1 Minor | 5+ | 6 | 34 |
| Jun 12, 12:00 | G1 Minor | 5 | 3 | 25 |
| Jun 16, 21:00 | G2 Moderate | 6 | 9 | 28 |
| Jun 19, 00:00 | G1 Minor | 5 | 3 | 35 |
| Jun 29, 15:00 | G3 Strong | 7- | 9 | 46 |
| Jul 7, 03:00 | G1 Minor | 5+ | 18 | 37 |
| Jul 14, 15:00 | G1 Minor | 5 | 3 | 18 |
| Jul 18, 12:00 | G2 Moderate | 6+ | 12 | 36 |
| Jul 19, 12:00 | G1 Minor | 5+ | 3 | 26 |
| Jul 23, 09:00 | G1 Minor | 5 | 3 | 19 |
| Jul 26, 18:00 | G5 Extreme | 9 | 21 | 153 |
| Jul 29, 00:00 | G3 Strong | 7 | 39 | 60 |
| Aug 7, 12:00 | G1 Minor | 5 | 3 | 23 |
| Aug 11, 12:00 | G1 Minor | 5 | 3 | 28 |
| Aug 14, 06:00 | G2 Moderate | 6+ | 18 | 48 |
| Aug 16, 18:00 | G1 Minor | 5 | 3 | 21 |
| Aug 31, 00:00 | G4 Severe | 8- | 9 | 52 |
| Sep 10, 09:00 | G1 Minor | 5 | 3 | 20 |
| Sep 16, 15:00 | G3 Strong | 7 | 12 | 34 |
| Sep 17, 21:00 | G4 Severe | 8- | 45 | 136 |
| Sep 21, 15:00 | G5 Extreme | 9 | 60 | 198 |
| Sep 27, 15:00 | G3 Strong | 7+ | 36 | 91 |
| Sep 30, 03:00 | G1 Minor | 5+ | 3 | 35 |
| Sep 30, 18:00 | G1 Minor | 5 | 3 | 35 |
| Oct 9, 06:00 | G1 Minor | 5+ | 3 | 31 |
| Oct 9, 21:00 | G1 Minor | 5 | 3 | 31 |
| Oct 20, 03:00 | G1 Minor | 5 | 3 | 24 |
| Oct 26, 21:00 | G3 Strong | 7- | 18 | 56 |
| Nov 12, 03:00 | G1 Minor | 5+ | 3 | 20 |
| Nov 21, 09:00 | G1 Minor | 5 | 3 | 25 |
| Nov 24, 12:00 | G2 Moderate | 6 | 3 | 25 |
| Dec 19, 12:00 | G1 Minor | 5+ | 6 | 27 |
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.