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Geomagnetic activity in September 2025
Mean Ap13.9No. 441 of 1138
G1+ days8
G3+ days2
Max Ap7430 Sep 2025
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 1 Sep 2025 | 6- | 14 | G2 |
| 2 Sep 2025 | 5+ | 31 | G1 |
| 6 Sep 2025 | 5o | 24 | G1 |
| 9 Sep 2025 | 5+ | 17 | G1 |
| 14 Sep 2025 | 5- | 11 | G1 |
| 15 Sep 2025 | 7- | 48 | G3 |
| 29 Sep 2025 | 5+ | 28 | G1 |
| 30 Sep 2025 | 7o | 74 | G3 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| September 2024 | 15.3 | 4 | 2 |
| September 2025 | 13.9 | 8 | 2 |
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 13.9 in September 2025, No. 441 of 1138 months since 1932; 8 days reached G1 or higher.