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Geomagnetic activity in September 1938
Mean Ap16.8No. 258 of 1138
G1+ days7
G3+ days4
Max Ap10015 Sep 1938
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 13 Sep 1938 | 5+ | 21 | G1 |
| 14 Sep 1938 | 6+ | 49 | G2 |
| 15 Sep 1938 | 7+ | 100 | G3 |
| 26 Sep 1938 | 5+ | 38 | G1 |
| 27 Sep 1938 | 7o | 30 | G3 |
| 28 Sep 1938 | 8- | 56 | G4 |
| 30 Sep 1938 | 7- | 32 | G3 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| September 1937 | 9.1 | 3 | 1 |
| September 1938 | 16.8 | 7 | 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 16.8 in September 1938, No. 258 of 1138 months since 1932; 7 days reached G1 or higher.