Geomagnetic Storms of 1948
57 geomagnetic storms of G1 or more began in 1948: 25 G1, 23 G2, 6 G3, 3 G4, 0 G5. The strongest began March 13, 1948 and reached Kp 8+, rank 89 of every storm since 1932.
By month
Every storm of 1948
Times are UT, when the first block at Kp 5 or more began.
| Began (UTC) | Level | Peak Kp | Hours | Highest daily Ap |
|---|---|---|---|---|
| Jan 3, 12:00 | G2 Moderate | 6 | 9 | 41 |
| Jan 17, 12:00 | G2 Moderate | 6- | 3 | 24 |
| Feb 3, 06:00 | G2 Moderate | 6- | 9 | 34 |
| Feb 15, 18:00 | G1 Minor | 5+ | 9 | 27 |
| Feb 23, 09:00 | G1 Minor | 5 | 6 | 26 |
| Mar 1, 03:00 | G2 Moderate | 6- | 6 | 41 |
| Mar 1, 21:00 | G1 Minor | 5+ | 15 | 41 |
| Mar 3, 03:00 | G1 Minor | 5+ | 3 | 24 |
| Mar 13, 09:00 | G4 Severe | 8+ | 63 | 140 |
| Apr 6, 18:00 | G2 Moderate | 6 | 3 | 24 |
| Apr 21, 00:00 | G3 Strong | 7- | 3 | 24 |
| Apr 22, 03:00 | G3 Strong | 7 | 12 | 50 |
| Apr 29, 06:00 | G1 Minor | 5+ | 3 | 19 |
| May 2, 12:00 | G1 Minor | 5 | 9 | 24 |
| May 7, 06:00 | G2 Moderate | 6 | 6 | 35 |
| May 9, 06:00 | G2 Moderate | 6+ | 6 | 32 |
| May 10, 15:00 | G1 Minor | 5 | 3 | 18 |
| May 13, 00:00 | G1 Minor | 5 | 3 | 17 |
| May 15, 00:00 | G2 Moderate | 6 | 9 | 47 |
| May 15, 21:00 | G3 Strong | 7 | 27 | 72 |
| May 21, 12:00 | G2 Moderate | 6+ | 15 | 45 |
| May 29, 12:00 | G1 Minor | 5+ | 6 | 27 |
| Jun 1, 03:00 | G1 Minor | 5+ | 12 | 34 |
| Jun 26, 15:00 | G1 Minor | 5 | 3 | 22 |
| Jul 4, 21:00 | G1 Minor | 5+ | 3 | 22 |
| Aug 4, 09:00 | G1 Minor | 5 | 3 | 20 |
| Aug 8, 00:00 | G4 Severe | 8- | 30 | 146 |
| Aug 9, 21:00 | G3 Strong | 7 | 36 | 74 |
| Aug 12, 06:00 | G2 Moderate | 6- | 15 | 30 |
| Aug 20, 00:00 | G2 Moderate | 6- | 6 | 29 |
| Sep 1, 00:00 | G1 Minor | 5 | 3 | 37 |
| Sep 1, 21:00 | G2 Moderate | 6 | 3 | 37 |
| Sep 4, 09:00 | G1 Minor | 5+ | 3 | 24 |
| Sep 7, 03:00 | G1 Minor | 5 | 3 | 15 |
| Sep 15, 21:00 | G1 Minor | 5+ | 9 | 22 |
| Sep 22, 21:00 | G1 Minor | 5+ | 3 | 16 |
| Sep 25, 12:00 | G1 Minor | 5 | 15 | 31 |
| Sep 29, 15:00 | G1 Minor | 5+ | 3 | 28 |
| Oct 1, 03:00 | G2 Moderate | 6+ | 12 | 46 |
| Oct 2, 03:00 | G2 Moderate | 6+ | 15 | 46 |
| Oct 3, 15:00 | G2 Moderate | 6- | 3 | 25 |
| Oct 5, 03:00 | G1 Minor | 5 | 3 | 16 |
| Oct 10, 06:00 | G2 Moderate | 6+ | 3 | 28 |
| Oct 14, 21:00 | G3 Strong | 7 | 24 | 51 |
| Oct 17, 21:00 | G4 Severe | 8+ | 45 | 94 |
| Oct 20, 18:00 | G3 Strong | 7- | 27 | 67 |
| Oct 22, 09:00 | G2 Moderate | 6- | 6 | 34 |
| Oct 23, 15:00 | G1 Minor | 5+ | 3 | 33 |
| Oct 24, 12:00 | G1 Minor | 5+ | 3 | 30 |
| Oct 27, 12:00 | G2 Moderate | 6 | 3 | 29 |
| Nov 1, 21:00 | G2 Moderate | 6+ | 30 | 56 |
| Nov 20, 09:00 | G2 Moderate | 6+ | 21 | 49 |
| Nov 24, 18:00 | G1 Minor | 5 | 3 | 23 |
| Dec 14, 03:00 | G1 Minor | 5+ | 3 | 26 |
| Dec 24, 03:00 | G2 Moderate | 6- | 6 | 21 |
| Dec 25, 15:00 | G2 Moderate | 6- | 12 | 33 |
| Dec 30, 18:00 | G2 Moderate | 6 | 24 | 29 |
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.