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Geomagnetic activity in December 1991
Mean Ap14.5No. 390 of 1138
G1+ days7
G3+ days0
Max Ap3627 Dec 1991
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 16 Dec 1991 | 5- | 20 | G1 |
| 17 Dec 1991 | 5+ | 35 | G1 |
| 21 Dec 1991 | 5- | 27 | G1 |
| 27 Dec 1991 | 6+ | 36 | G2 |
| 28 Dec 1991 | 5- | 23 | G1 |
| 29 Dec 1991 | 5+ | 29 | G1 |
| 30 Dec 1991 | 5- | 16 | G1 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| December 1990 | 7.0 | 0 | 0 |
| December 1991 | 14.5 | 7 | 0 |
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 14.5 in December 1991, No. 390 of 1138 months since 1932; 7 days reached G1 or higher.