Solar Flare WatchHome › Flare history › 1999
M9.8 solar flare on 1999-08-20
ClassM9.8NOAA report
Peak23:081999-08-20 UTC
Duration7 min
Peak flux9.8e-05W/m²
| Comparison | Value |
|---|---|
| Rank in year | 5 / 2025 |
| Other M/X flares that day | 2 |
| M/X flares that month | 25 |
| Solar cycle | Cycle 23 |
| Position on disk | S25E64 |
| 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
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.
← M6.0 1999-08-04M5.9 1999-08-21 →
About this page
A M9.8 flare that began 1999-08-20 23:03 UTC; No. 5 of 2,025 C-class-or-larger flares in 1999.