Solar flares on October 21, 2025
The most powerful solar flare in 24 hours
C3.7 (normal) flare - October 21 at 7:49 AM
Solar activity index
Value as of the end of the day on October 21, 2025
Solar X-ray emission over the past 2 days
Chart of solar X-ray emission (1-8 Å) from October 20, 2025 to October 21, 2025
Time zone — UTC+01 (London) — summer time
List of solar flares for October 21, 2025
The total number of solar flares of class C and higher — 3 flares
C class — 3 | M class — 0 | X class — 0
| Class | begin | max | end | region |
|---|---|---|---|---|
| C3.7 | 07:36 | 07:49 | 07:59 | — |
| C1.3 | 06:54 | 07:00 | 07:05 | 4248 |
| C2.1 | 00:16 | 00:24 | 00:33 | 4248 |