Viewing archive of Thursday, 23 October 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Oct 23 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
23 Oct 2025	134	007
24 Oct 2025	136	007
25 Oct 2025	138	017

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with several C-class flares recorded. The largest flare was a C3.2 flare (SIDC Flare 5857), peaking on October 23 at 05:08 UTC, associated with SIDC Sunspot Group 653 (magnetic type alpha), which recently rotated onto the visible side of the solar disk (N02E81). There are currently thirteen numbered active regions on the visible solar disk. SIDC Sunspot Group 644 (NOAA Active Region 4252; magnetic type alpha) and SIDC Sunspot Group 680 (magnetic type alpha) are approaching the west limb. A new region emerged and was numbered SIDC Sunspot Group 682 (magnetic type beta) near N15E51, but it remained quiet. The remaining active regions are relatively simple (magnetic type alpha or beta) and did not produce any significant flaring activity. Solar flaring activity is expected to be low over the next 24 hours, with C-class flares very likely and a small chance for M-class flares.

Coronal mass ejections

Two halo coronal mass ejections (SIDC CME 585 and SIDC CME 584) were observed in SOHO/LASCO-C2 imagery, starting at 20:36 UTC and 21:36 UTC on October 22, respectively. These CMEs are directed primarily toward the southeast and northwest from Earth's perspective. Analysis indicates that the sources of these CMEs were on the far side of the Sun. Therefore, no impact on the solar wind conditions near Earth is expected. No other Earth-directed CMEs have been detected in the available coronagraph imagery over the past 24 hours.

Solar wind

Over the past 24 hours, solar wind parameters (ACE and DSCOVR) reflected the waning influence of a high-speed stream (HSS). The solar wind speed ranged between 390 and 450 km/s. The interplanetary magnetic field reached values up to 10 nT, and its southward component fluctuated between -6 nT and 8 nT. A gradual transition to slow solar wind conditions is expected over the next days, with a chance of a weak enhancement from October 25 due to the possible arrival of a high-speed stream from a small, negative polarity coronal hole (SIDC Coronal Hole 133).

Geomagnetism

Geomagnetic conditions were quiet both globally and locally over Belgium (NOAA Kp: 1 to 2; K-Bel: 1 to 2). Mostly quiet geomagnetic conditions are expected over the next 24 hours.

Proton flux levels

The greater than 10 MeV proton flux, as measured by GOES-18, was slightly elevated over the past 24 hours, likely due to the fast halo coronal mass ejection (SIDC CME 583) observed in SOHO/LASCO-C2 coronagraph data starting around 20:24 UTC on October 21, but it remained below the 10 pfu threshold. The greater than 10 MeV GOES proton flux is expected to remain below the 10 pfu threshold 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. The greater than 2 MeV electron flux is expected to remain below the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence was at normal levels and is expected to be at normal levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 102, based on 12 stations.

Solar indices for 22 Oct 2025

Wolf number Catania	080
10cm solar flux	133
AK Chambon La Forêt	010
AK Wingst	004
Estimated Ap	004
Estimated international sunspot number	109 - 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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