Aurora & Space WeatherGeomagnetic activity in 1939
Mean Ap16.6
G1+103days
G3+26days
G51days
G1+ days by month
- January 1939
- February 1939
- March 1939
- April 1939
- May 1939
- June 1939
- July 1939
- August 1939
- September 1939
- October 1939
- November 1939
- December 1939
Nearby years (G1+ days)
37
55
50
71
95
103
88
100
92
128
64
Top 10 days by Ap
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 17 Apr 1939 | 8o | 135 | G4 |
| 22 Aug 1939 | 8- | 133 | G4 |
| 5 Jul 1939 | 7+ | 94 | G3 |
| 23 Apr 1939 | 8- | 92 | G4 |
| 23 Aug 1939 | 8- | 89 | G4 |
| 13 Oct 1939 | 8o | 89 | G4 |
| 12 Aug 1939 | 8- | 88 | G4 |
| 24 Apr 1939 | 9- | 79 | G5 |
| 14 Oct 1939 | 7- | 74 | G3 |
| 25 Feb 1939 | 7+ | 73 | G3 |
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
1939 had 103 G1+ storm days (No. 25 of 95 years) and 26 G3+ days.