Viewing archive of Friday, 26 December 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Dec 26 1250 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
26 Dec 2025	165	010
27 Dec 2025	163	010
28 Dec 2025	161	011

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with only C-class flares identified. The largest flare was a C6.9 flare (SIDC Flare 6493) peaking on December 26 at 09:14 UTC which was produced by an unnumbered group in the SE limb. A total of 9 numbered sunspot groups were identified on the disk over the past 24 hours. SIDC Sunspot Group 740 (NOAA Active Region 4321) is the most complex region with its Beta-Delta magnetic configuration and was growing over the past 24 hours. Solar flaring activity is expected to be low over the next 24 hours, with C-class flares very likely and a chance for M-class flares.

Coronal mass ejections

No Earth-directed coronal mass ejections (CME) were detected in the available coronagraph observations during last 24 hours.

Solar wind

Over the past 24 hours, solar wind parameters continued to reflect the waning influence of a high-speed stream (HSSs) from the elongated, posiitve polarity, recurrent coronal hole (SIDC Coronal Hole 128) which started to cross the central meridian on Dec 20. The solar wind speed decreased from 635 km/s to 485 km/s. The interplanetary magnetic field ranged between 0 nT and 7 nT, and the North-South component (Bz) ranged betweeen -5 nT and 5 nT. In the next 24 hours, enhanced solar wind conditions are expected to continue with the waning influence of HSSs. Further enhancements are possible if a glancing blow, associated with a coronal mass ejection (CME) that was observed lifting from the Sun on Dec 22 (SIDC CME 615), arrives late.

Geomagnetism

Geomagnetic conditions were globally at quiet (NOAA Kp 1 to 2), and locally over Belgium at quiet to unsetlled conditions (K BEL 1 to 3) during the past 24 hours. In the next 24 hours, we expect quiet to unsettled conditions (K 1 to 3) unless glancing blow, associated with a coronal mass ejection (CME) that was observed lifting from the Sun on Dec 22 (SIDC CME 615), arrives late and enhances the geomagnetic conditions to active to minor storm conditions (K 4 to 5).

Proton flux levels

The greater than 10 MeV GOES proton flux was below the threshold level over the past 24 hours and it is expected to remain so for the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux, as measured by GOES-18 and GOES-19 satellites, was above the 1000 pfu threshold for most of the time during the past 24 hours. It was in response to the high speed streams (HSS) from the southern, positive polarity, recurrent coronal hole (SIDC Coronal Hole 128) which started to cross the central meridian from Dec 20. The electron flux is expected to remain above this alert level during most of the next period. The electron fluence was at moderate levels and is expected to remain so.

Today's estimated international sunspot number (ISN): 117, based on 13 stations.

Solar indices for 25 Dec 2025

Wolf number Catania	///
10cm solar flux	163
AK Chambon La Forêt	014
AK Wingst	010
Estimated Ap	011
Estimated international sunspot number	122 - Based on 15 stations

Noticeable events summary

Provided by the Solar Influences Data analysis Center© - SIDC - Processed by SpaceWeatherLive

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