Geomagnetic Storms of 1977
40 geomagnetic storms of G1 or more began in 1977: 24 G1, 11 G2, 5 G3, 0 G4, 0 G5. The strongest began September 19, 1977 and reached Kp 7+, rank 289 of every storm since 1932.
By month
Every storm of 1977
Times are UT, when the first block at Kp 5 or more began.
| Began (UTC) | Level | Peak Kp | Hours | Highest daily Ap |
|---|---|---|---|---|
| Jan 11, 15:00 | G1 Minor | 5 | 3 | 14 |
| Jan 28, 21:00 | G1 Minor | 5+ | 3 | 13 |
| Jan 31, 00:00 | G1 Minor | 5+ | 3 | 19 |
| Feb 18, 03:00 | G1 Minor | 5+ | 3 | 17 |
| Feb 24, 18:00 | G1 Minor | 5 | 3 | 14 |
| Mar 9, 12:00 | G1 Minor | 5+ | 12 | 38 |
| Mar 26, 03:00 | G1 Minor | 5 | 3 | 16 |
| Apr 4, 00:00 | G1 Minor | 5+ | 3 | 24 |
| Apr 6, 15:00 | G3 Strong | 7 | 30 | 49 |
| Apr 19, 03:00 | G2 Moderate | 6+ | 12 | 48 |
| Apr 20, 15:00 | G1 Minor | 5 | 3 | 28 |
| Apr 25, 00:00 | G2 Moderate | 6- | 6 | 22 |
| May 2, 00:00 | G2 Moderate | 6+ | 24 | 66 |
| May 4, 15:00 | G1 Minor | 5+ | 6 | 19 |
| May 11, 15:00 | G2 Moderate | 6- | 15 | 24 |
| Jul 6, 12:00 | G2 Moderate | 6- | 6 | 28 |
| Jul 16, 09:00 | G1 Minor | 5 | 3 | 27 |
| Jul 20, 06:00 | G1 Minor | 5 | 3 | 29 |
| Jul 29, 00:00 | G3 Strong | 7- | 15 | 61 |
| Aug 5, 06:00 | G2 Moderate | 6 | 15 | 40 |
| Aug 11, 18:00 | G1 Minor | 5 | 3 | 28 |
| Aug 17, 09:00 | G2 Moderate | 6- | 6 | 29 |
| Aug 19, 00:00 | G1 Minor | 5 | 3 | 24 |
| Aug 25, 12:00 | G1 Minor | 5+ | 6 | 27 |
| Sep 13, 15:00 | G1 Minor | 5+ | 6 | 28 |
| Sep 19, 12:00 | G3 Strong | 7+ | 81 | 65 |
| Sep 23, 15:00 | G1 Minor | 5 | 3 | 21 |
| Sep 27, 00:00 | G2 Moderate | 6- | 6 | 24 |
| Oct 12, 03:00 | G1 Minor | 5 | 9 | 28 |
| Oct 18, 21:00 | G2 Moderate | 6 | 9 | 28 |
| Oct 22, 06:00 | G1 Minor | 5 | 3 | 22 |
| Oct 27, 09:00 | G3 Strong | 7+ | 24 | 62 |
| Nov 13, 15:00 | G1 Minor | 5 | 3 | 27 |
| Nov 14, 06:00 | G2 Moderate | 6- | 21 | 42 |
| Nov 25, 21:00 | G1 Minor | 5+ | 6 | 19 |
| Nov 27, 00:00 | G1 Minor | 5 | 3 | 12 |
| Dec 2, 00:00 | G3 Strong | 7 | 21 | 69 |
| Dec 11, 06:00 | G1 Minor | 5+ | 9 | 38 |
| Dec 12, 03:00 | G2 Moderate | 6- | 3 | 21 |
| Dec 17, 03:00 | G1 Minor | 5 | 3 | 12 |
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.