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Geomagnetic activity in September 1958
Mean Ap20.5No. 139 of 1138
G1+ days9
G3+ days4
Max Ap1314 Sep 1958
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 3 Sep 1958 | 7- | 64 | G3 |
| 4 Sep 1958 | 9- | 131 | G5 |
| 5 Sep 1958 | 8o | 71 | G4 |
| 8 Sep 1958 | 5+ | 20 | G1 |
| 9 Sep 1958 | 5- | 25 | G1 |
| 16 Sep 1958 | 5+ | 40 | G1 |
| 25 Sep 1958 | 7o | 82 | G3 |
| 26 Sep 1958 | 5o | 25 | G1 |
| 30 Sep 1958 | 5- | 20 | G1 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| September 1957 | 49.3 | 16 | 9 |
| September 1958 | 20.5 | 9 | 4 |
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 20.5 in September 1958, No. 139 of 1138 months since 1932; 9 days reached G1 or higher.