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Geomagnetic activity in May 1990
Mean Ap15.9No. 310 of 1138
G1+ days9
G3+ days2
Max Ap4726 May 1990
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 10 May 1990 | 6- | 33 | G2 |
| 11 May 1990 | 5+ | 24 | G1 |
| 18 May 1990 | 6+ | 31 | G2 |
| 20 May 1990 | 5- | 20 | G1 |
| 21 May 1990 | 5o | 22 | G1 |
| 22 May 1990 | 5+ | 32 | G1 |
| 26 May 1990 | 7+ | 47 | G3 |
| 27 May 1990 | 7- | 45 | G3 |
| 30 May 1990 | 5o | 23 | G1 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| May 1989 | 16.5 | 7 | 2 |
| May 1990 | 15.9 | 9 | 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 15.9 in May 1990, No. 310 of 1138 months since 1932; 9 days reached G1 or higher.