The last G4 geomagnetic storm occurred on November 12, 2025.

This severe event peaked around 0120 UTC, triggered by coronal mass ejections from intense solar activity, including an X5.1 flare earlier that week. It followed watches issued for potential G4 impacts, with auroras visible far south into Colorado.

Event Timeline

  • Buildup : Multiple CMEs from November 9-12, with the fastest hitting Earth and causing initial disturbances.
  • Peak Intensity : G4 levels confirmed at 0120 UTC on November 12, sustaining strong geomagnetic activity overnight.
  • Aftermath : Storm conditions lingered, enhancing aurora displays across northern and mid-latitudes.

Why It Matters

G4 storms like this one disrupt satellites, power grids, and communications due to rapid changes in Earth's magnetic field from solar wind interactions. No confirmed G4 events appear after this date up to early January 2026, though minor storms (like G1 on January 2) have occurred.

Recent Context

Earlier G4 storms hit on August 12, 2024, and May 31, 2025, amid heightened Solar Cycle 25 activity nearing its peak. Forums buzz with recaps, like Reddit's detailed October 2024 analysis, highlighting Dst indices and aurora chases.

TL;DR: November 12, 2025, marks the most recent G4 storm.

Information gathered from public forums or data available on the internet and portrayed here.