Solar Flare WatchHome › Flare history › 1999
M5.9 solar flare on 1999-08-21
ClassM5.9NOAA report
Peak22:141999-08-21 UTC
Duration6 min
Peak flux5.9e-05W/m²
| Comparison | Value |
|---|---|
| Rank in year | 13 / 2025 |
| Other M/X flares that day | 1 |
| M/X flares that month | 25 |
| Solar cycle | Cycle 23 |
| Position on disk | S24E52 |
| Active region | AR 8674 (29 flares) |
Compared with the strongest flares of 1999
X1.8
X1.4
X1.4
X1.1
M9.8
M8.0
M7.6
M7.4
M6.6
M6.2
M6.0
M6.0
Other M/X flares that day
| Date | Begin | Peak | Min | Class | Location | Region |
|---|---|---|---|---|---|---|
| 16:30 | 16:34 | 7 | M3.7 | S25E56 | 8674 |
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.
← M9.8 1999-08-20M5.5 1999-08-27 →
About this page
A M5.9 flare that began 1999-08-21 22:10 UTC; No. 13 of 2,025 C-class-or-larger flares in 1999.