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Solar flares in September 2021
C-class32
M-class1
X-class0
LargestM1.82021-09-23
Sunspot number51.9NOAA SWPC
Flares per day (C and above)
M/X flares per day
Same month a year earlier
| Month | C | M | X | Largest |
|---|---|---|---|---|
| September 2020 | 1 | 0 | 0 | C1.0 |
| September 2021 | 32 | 1 | 0 | M1.8 |
Top 15 flares
| Date | Begin | Peak | Min | Class | Location | Region |
|---|---|---|---|---|---|---|
| 2021-09-23 | 15:23 | 15:28 | 15 | M1.8 | – | – |
| 2021-09-08 | 17:11 | 17:30 | 37 | C8.3 | – | – |
| 2021-09-09 | 08:11 | 08:31 | 31 | C3.5 | – | – |
| 2021-09-24 | 06:56 | 07:01 | 8 | C2.9 | – | – |
| 2021-09-29 | 21:46 | 21:56 | 15 | C2.8 | – | – |
| 2021-09-18 | 08:18 | 08:27 | 14 | C2.6 | – | – |
| 2021-09-07 | 23:42 | 00:09 | 50 | C2.3 | – | – |
| 2021-09-08 | 12:46 | 12:58 | 17 | C2.3 | – | – |
| 2021-09-21 | 11:43 | 11:53 | 13 | C1.8 | – | – |
| 2021-09-25 | 19:11 | 19:17 | 9 | C1.7 | – | – |
| 2021-09-29 | 22:34 | 22:45 | 15 | C1.7 | – | – |
| 2021-09-19 | 01:04 | 01:15 | 17 | C1.6 | – | – |
| 2021-09-26 | 11:20 | 11:24 | 7 | C1.6 | – | – |
| 2021-09-18 | 07:48 | 08:15 | – | C1.5 | – | – |
| 2021-09-25 | 03:27 | 03:54 | 36 | C1.4 | – | – |
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
33 flares of class C or larger in September 2021; by M/X count it ranks 448 of 565 months.