In 1989 the planetary Kp peaked at 9.0 (G5) on 13 March 1989: 123 storm nights over the year, and 12.8% of its three-hour intervals at storm level.
| Month | Max Kp | Peak day | Storm nights | By class | At storm level | Avg Kp |
|---|---|---|---|---|---|---|
| January | 6.7 | 20 | 11 | G1×4G2×6G3×1 | 11.7% | 3.0 |
| February | 5.7 | 3 | 6 | G1×5G2×1 | 5.8% | 2.7 |
| March | 9.0 | 13 | 22 | G1×7G2×8G3×5G5×2 | 33.9% | 4.0 |
| April | 6.7 | 26 | 15 | G1×8G2×6G3×1 | 20.4% | 3.2 |
| May | 7.3 | 23 | 7 | G1×3G2×2G3×2 | 9.7% | 2.6 |
| June | 7.0 | 10 | 10 | G1×5G2×4G3×1 | 13.3% | 2.6 |
| July | 6.3 | 1 | 2 | G1×1G2×1 | 1.2% | 1.7 |
| August | 7.3 | 29 | 14 | G1×6G2×4G3×4 | 14.9% | 2.7 |
| September | 8.0 | 19 | 9 | G1×2G2×4G3×1G4×2 | 10.8% | 2.5 |
| October | 8.3 | 20 | 8 | G1×4G2×2G4×2 | 11.3% | 2.7 |
| November | 8.0 | 17 | 9 | G1×7G3×1G4×1 | 10.4% | 2.8 |
| December | 6.7 | 29 | 10 | G1×7G2×2G3×1 | 9.7% | 2.7 |
In the hall of storms: The Quebec blackout storm, 13 March 1989 · Kp 9.0 →
All-time record: Kp 9.0 — reached on 27 days, most recently 2024-05-11.
Ranked from the data: peak Kp, then intervals spent at 9.0. Nicknames and reach notes only where documented.
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