Solar flares on October 21, 2025
The most powerful solar flare in 24 hours
C4.7 (normal) flare - October 21 at 9:52 PM
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-04 (Oshawa) — summer time
List of solar flares for October 21, 2025
The total number of solar flares of class C and higher — 5 flares
C class — 5 | M class — 0 | X class — 0
| Class | begin | max | end | region |
|---|---|---|---|---|
| C4.7 | 21:07 | 21:52 | 22:03 | 4259 |
| C4.4 | 20:19 | 20:34 | 20:51 | 4257 |
| C1.5 | 19:36 | 19:47 | 19:53 | — |
| C3.7 | 02:36 | 02:49 | 02:59 | — |
| C1.3 | 01:54 | 02:00 | 02:05 | 4248 |