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Solar flares in September 1991
C-class246
M-class24
X-class2
LargestX3.31991-09-07
Flares per day (C and above)
M/X flares per day
Same month a year earlier
| Month | C | M | X | Largest |
|---|---|---|---|---|
| September 1990 | 149 | 16 | 0 | M5.3 |
| September 1991 | 246 | 24 | 2 | X3.3 |
Top 15 flares
| Date | Begin | Peak | Min | Class | Location | Region |
|---|---|---|---|---|---|---|
| 1991-09-07 | 19:11 | 19:35 | 70 | X3.3 | S11W50 | 6818 |
| 1991-09-08 | 09:06 | 09:16 | 43 | X1.0 | S13W58 | 6818 |
| 1991-09-29 | 15:13 | 15:31 | 146 | M7.3 | S21E32 | 6853 |
| 1991-09-24 | 07:51 | 07:55 | 28 | M6.1 | S10E88 | 6848 |
| 1991-09-05 | 01:04 | 01:11 | 30 | M4.4 | N24W65 | 6805 |
| 1991-09-07 | 09:40 | 10:16 | 102 | M4.1 | S11W48 | 6818 |
| 1991-09-26 | 12:24 | 12:28 | 32 | M3.4 | S19E75 | 6853 |
| 1991-09-10 | 20:46 | 21:11 | 51 | M3.0 | – | – |
| 1991-09-05 | 21:21 | 22:04 | 139 | M2.9 | S19W37 | 6811 |
| 1991-09-08 | 11:28 | 11:32 | 27 | M2.7 | S12E09 | 6820 |
| 1991-09-05 | 05:24 | 05:26 | 21 | M2.3 | N24W72 | 6805 |
| 1991-09-07 | 06:29 | 07:57 | 133 | M2.1 | S13W45 | 6818 |
| 1991-09-07 | 12:33 | 12:48 | 74 | M2.1 | S11W46 | 6818 |
| 1991-09-08 | 01:43 | 01:50 | 44 | M2.1 | S11W54 | 6818 |
| 1991-09-09 | 05:55 | 06:08 | 58 | M2.0 | S14W72 | 6818 |
All times UTC. Until June 2017 classes are NOAA's reports of the time (GOES-15 and earlier included a 0.7 scaling factor); later classes come from calibrated GOES-16/18 data, so the same flare reads about 1.4× larger. Do not compare the two periods directly.
About this page
272 flares of class C or larger in September 1991; by M/X count it ranks 124 of 565 months.