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Geomagnetic activity in October 1999
Mean Ap19.5No. 166 of 1138
G1+ days14
G3+ days1
Max Ap9122 Oct 1999
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 10 Oct 1999 | 6- | 33 | G2 |
| 11 Oct 1999 | 5o | 29 | G1 |
| 12 Oct 1999 | 5+ | 46 | G1 |
| 13 Oct 1999 | 5- | 23 | G1 |
| 14 Oct 1999 | 5o | 31 | G1 |
| 15 Oct 1999 | 5o | 31 | G1 |
| 16 Oct 1999 | 5- | 26 | G1 |
| 17 Oct 1999 | 5- | 21 | G1 |
| 21 Oct 1999 | 5o | 20 | G1 |
| 22 Oct 1999 | 8o | 91 | G4 |
| 23 Oct 1999 | 5+ | 32 | G1 |
| 24 Oct 1999 | 5- | 26 | G1 |
| 27 Oct 1999 | 5- | 19 | G1 |
| 28 Oct 1999 | 5+ | 21 | G1 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| October 1998 | 12.7 | 7 | 1 |
| October 1999 | 19.5 | 14 | 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.
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Mean Ap 19.5 in October 1999, No. 166 of 1138 months since 1932; 14 days reached G1 or higher.