Solar Flare WatchHome › Flare history › 2004
X1.8 solar flare on 2004-08-18
ClassX1.8NOAA report
Peak17:402004-08-18 UTC
Duration25 min
Peak flux1.8e-04W/m²
| Comparison | Value |
|---|---|
| Rank among X flares (1975 – Jun 2017) | 227 / 491 |
| Rank in year | 5 / 1046 |
| Other M/X flares that day | 0 |
| M/X flares that month | 28 |
| Solar cycle | Cycle 23 |
| Position on disk | S14W90 |
| Active region | AR 10656 (125 flares) |
Compared with the strongest flares of 2004
X3.6
X2.5
X2.0
X1.8
X1.8
X1.6
X1.3
X1.2
X1.1
X1.1
X1.0
X1.0
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.
← M9.4 2004-08-15X1.2 2004-10-30 →
About this page
A X1.8 flare that began 2004-08-18 17:29 UTC; No. 5 of 1,046 C-class-or-larger flares in 2004.