Solar flares on September 21, 2025
The most powerful solar flare in 24 hours
C6.6 (normal) flare - September 21 at 4:16 PM
Solar activity index
Value as of the end of the day on September 21, 2025
Solar X-ray emission over the past 2 days
Chart of solar X-ray emission (1-8 Å) from September 20, 2025 to September 21, 2025
Time zone — UTC-05 (Baton Rouge) — summer time
List of solar flares for September 21, 2025
The total number of solar flares of class C and higher — 10 flares
C class — 10 | M class — 0 | X class — 0
| Class | begin | max | end | region |
|---|---|---|---|---|
| C6.6 | 16:04 | 16:16 | 16:20 | 4223 |
| C3.3 | 12:33 | 12:43 | 12:50 | 4224 |
| C2.3 | 12:01 | 12:08 | 12:14 | 4220 |
| C2.1 | 09:42 | 09:45 | 09:49 | 4217 |
| C1.6 | 06:55 | 07:03 | 07:20 | 4228 |
| C1.6 | 04:53 | 05:01 | 05:06 | 4217 |
| C1.7 | 02:17 | 02:27 | 02:40 | — |
| C2.1 | 01:33 | 01:47 | 02:08 | 4220 |
| C2.8 | 00:27 | 00:33 | 00:49 | 4220 |
| C2.4 | 23:37 | 00:07 | 00:45 | 4217 |