Aurora & Space WeatherHome › Geomagnetic history › 2004
Geomagnetic activity in December 2004
Mean Ap10.9No. 674 of 1138
G1+ days3
G3+ days0
Max Ap2812 Dec 2004
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 12 Dec 2004 | 5+ | 28 | G1 |
| 28 Dec 2004 | 5- | 16 | G1 |
| 30 Dec 2004 | 5- | 18 | G1 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| December 2003 | 16.5 | 12 | 0 |
| December 2004 | 10.9 | 3 | 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 10.9 in December 2004, No. 674 of 1138 months since 1932; 3 days reached G1 or higher.