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Geomagnetic storm on 22 Sep 1999 (G4)
Max Kp8oG4
Ap50No. 4 in 1999
Consecutive G1+ days2
Ap rank938since 1932
Kp by 3-hour slot (UTC)
3o
2o
2o
3-
5o
4-
6o
8o
The days around it
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 19 Sep 1999 | 3+ | 9 | – |
| 20 Sep 1999 | 3+ | 8 | – |
| 21 Sep 1999 | 4- | 11 | – |
| 22 Sep 1999 | 8o | 50 | G4 |
| 23 Sep 1999 | 6+ | 28 | G2 |
| 24 Sep 1999 | 2o | 5 | – |
| 25 Sep 1999 | 1+ | 4 | – |
Highest-Ap days of 1999
91
80
53
50
47
46
46
43
43
41
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
Max Kp 8o, Ap 50: No. 938 of 34,615 days since 1932 by Ap.