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Geomagnetic activity in April 1991
Mean Ap16.5No. 268 of 1138
G1+ days8
G3+ days2
Max Ap5929 Apr 1991
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 1 Apr 1991 | 5- | 29 | G1 |
| 3 Apr 1991 | 5+ | 37 | G1 |
| 4 Apr 1991 | 7- | 50 | G3 |
| 25 Apr 1991 | 5- | 17 | G1 |
| 27 Apr 1991 | 5+ | 24 | G1 |
| 28 Apr 1991 | 5o | 33 | G1 |
| 29 Apr 1991 | 7- | 59 | G3 |
| 30 Apr 1991 | 5+ | 34 | G1 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| April 1990 | 27.3 | 17 | 3 |
| April 1991 | 16.5 | 8 | 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 16.5 in April 1991, No. 268 of 1138 months since 1932; 8 days reached G1 or higher.