G1 – Minor Geomagnetic Storm Watch issued for December 22 and 23, 2025

A G1 – Minor Geomagnetic Storm Watch has been issued by the NOAA Space Weather Prediction Center, effective for December 22 and 23, 2025. According to the official alert, no geomagnetic storm conditions are expected on December 21, but G1 – Minor levels are likely on both December 22 and 23. This Watch supersedes any prior watches in effect.

Potential impacts from a G1 – Minor Geomagnetic Storm include weak power grid fluctuations primarily in areas poleward of 60 degrees geomagnetic latitude. Minor impacts to satellite operations are possible. Aurora may become visible at high latitudes, such as the northern tier of the United States including northern Michigan and Maine, according to NOAA SWPC space weather scales.

Forecast discussion indicates that the expected G1 – Minor geomagnetic storming on December 22 is due to the anticipated onset of corotating interaction region (CIR) effects followed by positive polarity coronal hole high speed stream (CH HSS) influences. The geomagnetic field is forecast to remain mostly quiet until these conditions arrive.