Aurora & Space WeatherHome › Geomagnetic history › 1974
Geomagnetic activity in September 1974
Mean Ap23.2No. 90 of 1138
G1+ days15
G3+ days2
Max Ap8816 Sep 1974
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 1 Sep 1974 | 5o | 24 | G1 |
| 2 Sep 1974 | 5+ | 32 | G1 |
| 4 Sep 1974 | 5o | 20 | G1 |
| 5 Sep 1974 | 5- | 19 | G1 |
| 15 Sep 1974 | 8- | 73 | G4 |
| 16 Sep 1974 | 8o | 88 | G4 |
| 18 Sep 1974 | 6- | 19 | G2 |
| 19 Sep 1974 | 6- | 34 | G2 |
| 20 Sep 1974 | 6- | 35 | G2 |
| 21 Sep 1974 | 6+ | 43 | G2 |
| 22 Sep 1974 | 5- | 24 | G1 |
| 24 Sep 1974 | 5+ | 26 | G1 |
| 25 Sep 1974 | 5+ | 30 | G1 |
| 26 Sep 1974 | 5o | 38 | G1 |
| 27 Sep 1974 | 5o | 25 | G1 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| September 1973 | 14.1 | 7 | 2 |
| September 1974 | 23.2 | 15 | 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 23.2 in September 1974, No. 90 of 1138 months since 1932; 15 days reached G1 or higher.