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Geomagnetic activity in April 1939
Mean Ap28.0No. 32 of 1138
G1+ days14
G3+ days5
Max Ap13517 Apr 1939
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 1 Apr 1939 | 5- | 28 | G1 |
| 4 Apr 1939 | 5o | 18 | G1 |
| 10 Apr 1939 | 5+ | 42 | G1 |
| 11 Apr 1939 | 5o | 30 | G1 |
| 12 Apr 1939 | 5- | 17 | G1 |
| 17 Apr 1939 | 8o | 135 | G4 |
| 18 Apr 1939 | 6o | 42 | G2 |
| 19 Apr 1939 | 7- | 45 | G3 |
| 20 Apr 1939 | 5o | 27 | G1 |
| 22 Apr 1939 | 5- | 20 | G1 |
| 23 Apr 1939 | 8- | 92 | G4 |
| 24 Apr 1939 | 9- | 79 | G5 |
| 25 Apr 1939 | 7+ | 61 | G3 |
| 27 Apr 1939 | 6o | 14 | G2 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| April 1938 | 18.3 | 8 | 3 |
| April 1939 | 28.0 | 14 | 5 |
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 28.0 in April 1939, No. 32 of 1138 months since 1932; 14 days reached G1 or higher.