Viewing archive of Monday, 15 December 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Dec 15 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
15 Dec 2025	119	007
16 Dec 2025	119	008
17 Dec 2025	119	007

Solar Active Regions and flaring

Solar flaring activity during the last 24 hours has been low, with only a few C-class flares. The strongest flare was a C2.3 flare (SIDC Flare 6425), peaking at 17:13 UTC on December 14, associated with SIDC Sunspot Group 722 (NOAA Active Region 4307, magnetic type beta). There are currently seven numbered active regions on the solar disk. The most complex ones have a beta magnetic type. SIDC Sunspot Group 718 (NOAA Active Region 4304, magnetic type beta) is currently rotating across the west limb. SIDC Sunspot Group 725 (magnetic type beta) and SIDC Sunspot Group 726 (magnetic type alpha) have emerged in the northeast quadrant. SIDC Sunspot Group 727 (NOAA active region 4309, magnetic type beta) has emerged in the southwest quadrant. The solar flaring activity is expected to be low over the next 24 hours, with C-class flares expected and a chance for M-class flares.

Coronal mass ejections

A wide Coronal Mass Ejection (SIDC CME 610) was observed in LASCO/C2 and STEREO/COR2 coronagraph imagery, lifting off the southwest quadrant, starting from around 00:25 UTC on December 15. It is most likely associated with a prominence eruption near the southwest limb and it is not expected to impact Earth. No other Earth-directed Coronal Mass Ejections were observed in the available coronagraph imagery over the last 24 hours.

Coronal holes

A north-south elongated, negative polarity coronal hole (returning SIDC Coronal Hole 136) is crossing the central meridian. An associated high-speed stream is expected to arrive at Earth starting from the UTC evening on December 17. A second, southern, mid-latitude, negative polarity coronal hole (returning SIDC Coronal Hole 137) is crossing the central meridian. An associated high-speed stream may arrive at Earth starting from the UTC evening on December 17.

Solar wind

The solar wind conditions (ACE) during the last 24 hours indicate a gradual return to the slow solar wind regime, after the arrival of a high-speed stream from the northern, negative polarity coronal hole (SIDC Coronal Hole 142). The solar wind speed decreased from 580 to around 450 km/s. The interplanetary magnetic field increased from 3 to 7 nT. The Bz component was mostly positive with values between 1 nT and 3 nT until 03:00 UTC on December 15, and then varied between -2 nT and 2 nT. The interplanetary magnetic field angle phi was mostly negative. A further decrease towards the slow solar wind regime is expected over the next 24 hours, with enhancements still possible under the waning influence of the high-speed stream from SIDC Coronal Hole 142.

Geomagnetism

Geomagnetic conditions globally and locally were at quiet levels (NOAA Kp 1 to 2-, K Bel 1 to 2) during the last 24 hours. Mostly quiet conditions are expected over the next 24 hours, with a small change of isolated periods of unsettled conditions.

Proton flux levels

The greater than 10 MeV proton flux was below the 10 pfu threshold during the last 24 hours. It is expected to remain below the threshold level over the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 and GOES 19 was below the 1000 pfu threshold during the last 24 hours. It is expected to gradually increase over the next 24 hours. The 24-hour electron fluence is presently at normal levels and is expected to remain so over the next 24 hours.

Today's estimated international sunspot number (ISN): 070, based on 14 stations.

Solar indices for 14 Dec 2025

Wolf number Catania	///
10cm solar flux	119
AK Chambon La Forêt	008
AK Wingst	008
Estimated Ap	006
Estimated international sunspot number	071 - Based on 10 stations

Noticeable events summary

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

All times in UTC

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