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Geomagnetic activity in May 1999
Mean Ap8.0No. 935 of 1138
G1+ days2
G3+ days0
Max Ap2718 May 1999
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 13 May 1999 | 5o | 25 | G1 |
| 18 May 1999 | 5o | 27 | G1 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| May 1998 | 17.7 | 7 | 4 |
| May 1999 | 8.0 | 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 8.0 in May 1999, No. 935 of 1138 months since 1932; 2 days reached G1 or higher.