Viewing archive of Tuesday, 30 December 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Dec 30 1231 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

Moderate (ISES: Major) magstorm expected (A>=50 or K=6)

Solar protons

Quiet

	10cm flux	Ap
30 Dec 2025	204	014
31 Dec 2025	210	042
01 Jan 2026	203	018

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with only C-class flares recorded. The largest flare was an C6.4 flare peaking on December 29 at 20:40 UTC. There are currently 9 numbered regions on the disk. SIDC Sunspot Group 745 (NOAA Active Region 4325) grew over the period and has a Beta-Delta magnetic configuration. Two of the other most complex regions, SIDC Sunspot Groups 744 and 740 (NOAA Active Regions 4324 and 4321, respectively) were stable but produced C-class flares. SIDC Sunspot Group 735 (NOAA Active Region 4317, magnetic type beta) was quiet and stable. Three new active regions emerged and were numbered, but these were simple and mostly quiet. Solar flaring activity is expected to be moderate over the next 24 hours, with M-class flares expected and a chance for X-class flares.

Coronal mass ejections

The partial halo Coronal Mass Ejection (CME) reported yesterday, seen in LASCO-C2 data from 23:00 UTC on December 28, has been analysed and a glancing blow is expected at Earth from January 01. No other Earth-directed CMEs were observed in the available coronagraph imagery.

Coronal holes

A small positive polarity coronal hole in the southern hemisphere (SIDC Coronal Hole 143) began to transit the central meridian on December 30.

Solar wind

Over the past 24 hours, solar wind parameters reflected a slow solar wind regime. The solar wind speed ranged between 380 and 440 km/s. The interplanetary magnetic field ranged between 3 and 8 nT, and Bz had a minimum of -5 nT. The interplanetary magnetic field phi angle was mostly in the positive sector (directed away from the Sun). From early on December 31, enhanced solar wind conditions are expected due the high speed stream arrival associated with SIDC Coronal Hole 140 (negative polarity) which began to cross the central meridian on December 28.

Geomagnetism

Geomagnetic conditions were at quiet levels globally (NOAA Kp 1 to 2) and locally (K BEL 1 to 2) over the past 24 hours. Quiet to unsettled conditions are expected for Dec 30 and from December 31 minor storm conditions are expected with possible moderate storm intervals possible, due to the expected high speed stream arrival.

Proton flux levels

The greater than 10 MeV proton flux was below the 10 pfu threshold over the past 24 hours. It is expected to remain below this threshold level over 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 mostly above the 1000 pfu threshold for past 24 hours. The greater than 2 MeV electron flux is expected to again exceed the 1000 pfu threshold over the next 24 hours but is expected to decrease from December 31, due to the anticipated high speed stream arrival. The electron fluence was at moderate levels and is expected to remain so for the next 24 hours.

Today's estimated international sunspot number (ISN): 136, based on 16 stations.

Solar indices for 29 Dec 2025

Wolf number Catania	150
10cm solar flux	196
AK Chambon La Forêt	010
AK Wingst	008
Estimated Ap	008
Estimated international sunspot number	145 - Based on 16 stations

Noticeable events summary

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

All times in UTC

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