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Geomagnetic activity in September 1977
Mean Ap15.9No. 304 of 1138
G1+ days8
G3+ days2
Max Ap6421 Sep 1977
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 13 Sep 1977 | 5+ | 28 | G1 |
| 19 Sep 1977 | 6o | 42 | G2 |
| 20 Sep 1977 | 6- | 44 | G2 |
| 21 Sep 1977 | 7+ | 64 | G3 |
| 22 Sep 1977 | 7- | 63 | G3 |
| 23 Sep 1977 | 5o | 21 | G1 |
| 26 Sep 1977 | 5- | 18 | G1 |
| 27 Sep 1977 | 6- | 24 | G2 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| September 1976 | 13.1 | 5 | 0 |
| September 1977 | 15.9 | 8 | 2 |
Dates and time slots are UTC. Kp is the 3-hourly planetary geomagnetic index (0–9); Ap is the daily average disturbance. G1–G5 follow the NOAA storm scale (Kp 5- and above counted as G1). Aurora visibility also depends on weather and location. The latest values are preliminary.
About this page
Mean Ap 15.9 in September 1977, No. 304 of 1138 months since 1932; 8 days reached G1 or higher.