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Geomagnetic activity in December 1987
Mean Ap9.2No. 821 of 1138
G1+ days2
G3+ days0
Max Ap3916 Dec 1987
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 10 Dec 1987 | 5+ | 28 | G1 |
| 16 Dec 1987 | 6- | 39 | G2 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| December 1986 | 8.5 | 3 | 0 |
| December 1987 | 9.2 | 2 | 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 9.2 in December 1987, No. 821 of 1138 months since 1932; 2 days reached G1 or higher.