Solar flux 116 and estimated planetary A-index 18. The estimated planetary K-index at 2100 UTC on 18 December was 3.00. Space weather for the past 24 hours has been minor. Geomagnetic storms reaching the G1 level occurred.

Forecast Issued at 2200Z on 18 Dec 2025

Solar Activity Forecast: Solar activity is expected to be low with a slight chance for an M-class flare on days one, two, and three (19 Dec, 20 Dec, 21 Dec).

Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one and two (19 Dec, 20 Dec) and quiet levels on day three (21 Dec).