Solar Flare WatchHome › Flare history › 1991
X1.0 solar flare on 1991-07-18
ClassX1.0NOAA report
Peak14:281991-07-18 UTC
Duration87 min
Peak flux1.0e-04W/m²
| Comparison | Value |
|---|---|
| Rank among X flares (1975 – Jun 2017) | 416 / 491 |
| Rank in year | 51 / 3297 |
| Other M/X flares that day | 0 |
| M/X flares that month | 35 |
| Solar cycle | Cycle 22 |
| Position on disk | N06E88 |
| Active region | AR 6734 (29 flares) |
Compared with the strongest flares of 1991
X12.0
X12.0
X12.0
X12.0
X12.0
X10.0
X10.0
X9.4
X7.1
X6.1
X5.5
X5.3
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.
← X1.1 1991-07-17X1.0 1991-07-20 →
About this page
A X1.0 flare that began 1991-07-18 14:16 UTC; No. 51 of 3,297 C-class-or-larger flares in 1991.