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Geomagnetic activity in September 1940
Mean Ap14.0No. 436 of 1138
G1+ days6
G3+ days2
Max Ap4527 Sep 1940
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 1 Sep 1940 | 5o | 22 | G1 |
| 7 Sep 1940 | 5+ | 30 | G1 |
| 14 Sep 1940 | 5+ | 15 | G1 |
| 26 Sep 1940 | 8- | 44 | G4 |
| 27 Sep 1940 | 7- | 45 | G3 |
| 28 Sep 1940 | 6- | 42 | G2 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| September 1939 | 13.2 | 7 | 1 |
| September 1940 | 14.0 | 6 | 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 14.0 in September 1940, No. 436 of 1138 months since 1932; 6 days reached G1 or higher.