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Geomagnetic activity in April 1940
Mean Ap17.6No. 225 of 1138
G1+ days6
G3+ days5
Max Ap983 Apr 1940
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 1 Apr 1940 | 7- | 66 | G3 |
| 2 Apr 1940 | 7o | 34 | G3 |
| 3 Apr 1940 | 8o | 98 | G4 |
| 22 Apr 1940 | 5- | 18 | G1 |
| 25 Apr 1940 | 8o | 70 | G4 |
| 26 Apr 1940 | 7o | 43 | G3 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| April 1939 | 28.0 | 14 | 5 |
| April 1940 | 17.6 | 6 | 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 17.6 in April 1940, No. 225 of 1138 months since 1932; 6 days reached G1 or higher.