G1 – Minor Geomagnetic Storm Alert issued on June 25

A G1 – Minor Geomagnetic Storm Alert was issued at 03:56 UTC on June 25, 2026, after the geomagnetic K-index reached 5 at 03:43 UTC. The alert is in place for the synoptic period 03:00–06:00 UTC and remains active according to the latest NOAA SWPC alert.

The G1 – Minor classification means impacts are possible primarily poleward of 60 degrees geomagnetic latitude. Weak power grid fluctuations may occur. Minor effects on satellite operations are possible. Additionally, aurora may be visible at high latitudes, including regions such as northern Michigan and Maine in the United States.

This current G1 – Minor storm was triggered by persistent elevated solar wind conditions associated with the influence of a negative polarity coronal hole high speed stream (CH HSS). Solar wind speeds increased significantly, and the geomagnetic field responded with a shift to unsettled and active levels. Forecasts indicate these elevated solar wind conditions may continue through June 27, 2026.