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Geomagnetic activity in April 1990
Mean Ap27.3No. 38 of 1138
G1+ days17
G3+ days3
Max Ap12410 Apr 1990
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 9 Apr 1990 | 6- | 34 | G2 |
| 10 Apr 1990 | 8o | 124 | G4 |
| 11 Apr 1990 | 7- | 64 | G3 |
| 12 Apr 1990 | 8- | 99 | G4 |
| 13 Apr 1990 | 5+ | 38 | G1 |
| 14 Apr 1990 | 6o | 45 | G2 |
| 15 Apr 1990 | 5o | 24 | G1 |
| 17 Apr 1990 | 6o | 40 | G2 |
| 18 Apr 1990 | 5+ | 24 | G1 |
| 20 Apr 1990 | 5o | 18 | G1 |
| 21 Apr 1990 | 5- | 13 | G1 |
| 22 Apr 1990 | 5- | 16 | G1 |
| 23 Apr 1990 | 6- | 37 | G2 |
| 24 Apr 1990 | 6o | 30 | G2 |
| 26 Apr 1990 | 5+ | 16 | G1 |
| 29 Apr 1990 | 5o | 30 | G1 |
| 30 Apr 1990 | 6- | 19 | G2 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| April 1989 | 22.7 | 15 | 1 |
| April 1990 | 27.3 | 17 | 3 |
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 27.3 in April 1990, No. 38 of 1138 months since 1932; 17 days reached G1 or higher.