Viewing archive of Monday, 25 August 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Aug 25 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

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

	10cm flux	Ap
25 Aug 2025	152	007
26 Aug 2025	156	016
27 Aug 2025	160	007

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours, with 2 M-class flares identified. They both originated at a (yet) unnumbered region rotating into view over the east limb (close to the equator). The largest flare was an M4.5 flare peaking at 05:24 UTC. Most of the flaring activity (including several C-class flares) is located on the eastern hemisphere of the Sun. Solar flaring activity is expected to be moderate over the next 24 hours, with M-class flares likely and a small chance for X-class flares.

Coronal mass ejections

No Earth-directed Coronal Mass Ejections (CMEs) have been observed in the last 24 hours.

Coronal holes

SIDC Coronal Hole 126 (northern mid-latitude coronal hole with negative polarity) is located in the western hemisphere and its related high speed solar wind streamm may arrive to the Earth on 26 August.

Solar wind

The Earth is inside slow solar wind with speeds around 410 km/s and interplanetary magnetic fields of about 8 nT (directed towards the Sun, negative polarity). In about 24 hours, the arrival of a high speed stream is expected.

Geomagnetism

Geomagnetic conditions have been quiet (Kp and B_Bel between 0 and 2). Similar conditions are expected until the arrival of the high speed solar wind stream on 26 August (mostly active conditions expected then).

Proton flux levels

The greater than 10 MeV proton flux has been slowly and gradually increasing since 22 August, and it is now close to the 10 pfu threshold. A warning condition forecast is issued for the next 48 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux as measured by GOES 18 and 19 remained below the 1000 pfu alert threshold (except for a minimal crossing of the threshold around 16:00 and 23:00 UTC on 24 August), similar conditions expected for the next 24 hours. The 24 h electron fluence was at normal levels and is expected to remain so.

Today's estimated international sunspot number (ISN): 136, based on 26 stations.

Solar indices for 24 Aug 2025

Wolf number Catania	///
10cm solar flux	152
AK Chambon La Forêt	008
AK Wingst	006
Estimated Ap	005
Estimated international sunspot number	111 - Based on 29 stations

Noticeable events summary

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

All times in UTC

<< Go to daily overview page