Aurora & Space WeatherHome › Geomagnetic history › 1939
Geomagnetic activity in May 1939
Mean Ap21.4No. 118 of 1138
G1+ days16
G3+ days2
Max Ap561 May 1939
Daily Ap
Daily max Kp
| Date | Max Kp | Ap | Level |
|---|---|---|---|
| 1 May 1939 | 7- | 56 | G3 |
| 2 May 1939 | 6+ | 48 | G2 |
| 3 May 1939 | 5- | 23 | G1 |
| 5 May 1939 | 6o | 27 | G2 |
| 6 May 1939 | 6o | 40 | G2 |
| 7 May 1939 | 7- | 51 | G3 |
| 8 May 1939 | 6- | 34 | G2 |
| 9 May 1939 | 6- | 26 | G2 |
| 16 May 1939 | 5o | 20 | G1 |
| 20 May 1939 | 5- | 17 | G1 |
| 22 May 1939 | 5+ | 30 | G1 |
| 23 May 1939 | 5+ | 26 | G1 |
| 24 May 1939 | 5+ | 30 | G1 |
| 25 May 1939 | 5o | 28 | G1 |
| 28 May 1939 | 5+ | 22 | G1 |
| 29 May 1939 | 5+ | 34 | G1 |
Same month a year earlier
| Month | Mean Ap | G1+ | G3+ |
|---|---|---|---|
| May 1938 | 17.8 | 9 | 3 |
| May 1939 | 21.4 | 16 | 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 21.4 in May 1939, No. 118 of 1138 months since 1932; 16 days reached G1 or higher.