Space weather / EVENT RECORD
ALERT: Geomagnetic K-index of 4
NOAA SWPC · Every measurement below belongs to the selected record.
Read the source-series history ↗- Bulletin issued
- 2026-10-21 04:29:25.873Z
- Source update / publication
- 2026-10-21 04:29:25.873Z
ALERT: Geomagnetic K-index of 4 · Threshold Reached: 2026 Oct 21 0429 UTC · Synoptic Period: 0300-0600 · Active Warning: YES · Comment: · NOAA Space Weather Scale descriptions can be found at · www.swpc.noaa.gov/noaa-scales-explanation
Read the original NOAA SWPC record ↗This is a source-linked archive. Source measurements and assessments can change. An archived bulletin is not evidence that a warning is currently active.
In the daily journal
21 October 2026 ↗SOURCE ID swpc:K04A:2026-10-21T04:29:25.873Z