A G3 – Strong geomagnetic storm watch is in effect following a powerful M8.1 solar flare from geoeffective Active Region 4299 at 20:39 UTC on December 6, 2025. The resulting full-halo coronal mass ejection (CME) is expected to impact Earth between early and midday UTC on December 9, possibly producing periods of strong geomagnetic storming.
A strong solar flare measuring M8.1 erupted from Active Region 4299 at 20:39 UTC on December 6, 2025. The event started at 20:29 and ended at 20:49 UTC. A full-halo coronal mass ejection was produced, with impact expected early to midday on December 9, potentially causing periods of G3 – Strong geomagnetic storming.
A strong M6.0 solar flare erupted from Region 4300 at 02:50 UTC on December 4, 2025, producing a non-Earth-directed CME. The flare occurred as Earth’s geomagnetic field remained in storm conditions, including a G3 – Strong interval driven by the arrival of a negative CH HSS and the flank of the CME launched on December 1. Solar wind parameters showed elevated density, strong IMF values, and Bz reaching −15 nT before transitioning to high-speed stream conditions.
NOAA’s Space Weather Prediction Center (SWPC) issued a G2 – Moderate geomagnetic storm watch for December 3 and 4, 2025, following a coronal mass ejection (CME) associated with the X1.9 solar flare from Active Region 4299 on December 1. The CME is expected to deliver a glancing blow to Earth’s magnetic field, coinciding with a co-rotating interaction region (CIR) and a sector boundary crossing, increasing the potential for moderate geomagnetic storming and visible auroras at mid-latitudes.
A major solar flare registered as X1.9 erupted from Active Region 4299 at 02:49 UTC on December 1, 2025. The event started at 02:27 and ended at 03:05 UTC. This region is currently making its second run through the Earth-side of the Sun, after producing multiple X-class flares in early November.
UK researchers report that radiation levels at commercial flight altitudes reached their highest values in 20 years following the X5-class solar flare on November 11, 2025, with the resulting Ground Level Enhancement driving single-event upset rates in avionics not seen since 2006.
A major long-duration solar flare measuring X4.0 erupted from Active Region 4274 at 08:30 UTC on November 14, 2025, producing a fast CME. The event started at 07:44 and ended at 08:40 UTC.
Coronal mass ejections produced by a long-duration X1.7 on November 9 and X1.2 on November 10 appear to have merged on their way to Earth and impacted our planet at 23:00 UTC on November 11, sparking G4 – Severe geomagnetic storming. Another CME, produced by a major X5.1 flare on November 11, is expected to impact Earth by the end of November 12, causing another round of severe geomagnetic storming. Aurora watchers have already reported impressive sightings as far south as Zacatecas, Mexico.
A major X5.1 solar flare erupted from Active Region 4274 at 10:04 UTC on November 11, 2025, producing a large Earth-directed coronal mass ejection (CME). NOAA SWPC issued a geomagnetic storm watch predicting G4 – Severe or greater conditions for November 12, G3 – Strong for November 13, and G1 – Minor for November 14. On November 12 and 13, aurora may be visible as far south as Alabama and northern California.
A major solar flare registered as X5.1 erupted from Active Region 4274 at 10:04 UTC on November 11, 2025. The event started at 09:49 UTC and ended at 10:17 UTC.
