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Geomagnetic activity in May 1991
Mean Ap17.7No. 220 of 1138
G1+ days13
G3+ days1
Max Ap5231 May 1991
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 1 May 1991 | 5- | 27 | G1 |
| 2 May 1991 | 6o | 45 | G2 |
| 13 May 1991 | 5o | 27 | G1 |
| 14 May 1991 | 6- | 33 | G2 |
| 16 May 1991 | 5+ | 15 | G1 |
| 17 May 1991 | 6o | 35 | G2 |
| 23 May 1991 | 5- | 21 | G1 |
| 24 May 1991 | 5o | 26 | G1 |
| 25 May 1991 | 6- | 35 | G2 |
| 26 May 1991 | 5- | 23 | G1 |
| 28 May 1991 | 5o | 31 | G1 |
| 29 May 1991 | 5+ | 22 | G1 |
| 31 May 1991 | 7- | 52 | G3 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| May 1990 | 15.9 | 9 | 2 |
| May 1991 | 17.7 | 13 | 1 |
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 17.7 in May 1991, No. 220 of 1138 months since 1932; 13 days reached G1 or higher.