Viewing archive of Wednesday, 15 October 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Oct 15 1239 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
15 Oct 2025	160	011
16 Oct 2025	165	029
17 Oct 2025	170	012

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours with 6 M-class flares recorded. The largest flare was an M4.8 flare (SIDC Flare 5780) peaking on October 15 at 04:15 UTC, which was produced by SIDC Sunspot Group 639 (NOAA Active Region 4246). This region continued to increase in size and complexity and was responsible for most of the M-class flaring activity. SIDC Sunspot group 621 (NOAA Active region 4248) also increased in complexity and produced an M2.0 flare (SIDC Flare 5759) peaking on October 14 at 12:47 UTC. The remaining regions on disk were mostly quiet and either stable or in decay. The 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

No new Earth directed Coronal Mass Ejections (CMEs) were observed in the available coronagraph imagery.

Solar wind

The solar wind conditions reflected the ongoing waning influence of the high-speed stream associated with the large equatorial coronal hole that first began to cross the central meridian on October 08 (SIDC Coronal Hole 116). The solar wind speed gradually decreased from 650 km/s to around 500 km/s. The interplanetary magnetic field ranged between 1 and 6 nT. Bz ranged between -4 nT and 5 nT. Over the next 24 hours the solar wind conditions may become enhanced from early on October 16, due to a possible CME arrival from the CME observed on October 12. Further disturbances may be expected late on October 16 due to the glancing blow from the CMEs observed on October 13.

Geomagnetism

Geomagnetic conditions reached active conditions (Kp 4- ), due to the ongoing high speed stream influence. Locally, active conditions were observed (K Bel 3). Unsettled to active conditions are expected on October 15, with periods of minor storm conditions (Kp 5) possible from October 16 in response to the possible CME 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. There is a small chance of an increase related to any high-level flaring, particularly from SIDC Sunspot Group 639 (NOAA Active Region 4246).

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 and GOES 19 exceeded the 1000 pfu threshold. The greater than 2 MeV electron flux is expected to again exceed the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence was at moderate levels and is expected to be at moderate levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 116, based on 08 stations.

Solar indices for 14 Oct 2025

Wolf number Catania	172
10cm solar flux	154
AK Chambon La Forêt	015
AK Wingst	008
Estimated Ap	008
Estimated international sunspot number	125 - Based on 19 stations

Noticeable events summary

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

All times in UTC

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