Viewing archive of Monday, 25 May 2026

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2026 May 25 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
25 May 2026	136	008
26 May 2026	138	010
27 May 2026	140	011

Solar Active Regions and flaring

Solar flaring activity has been low over the past 24 hours, with few C-class flares. The strongest flare was a C3.7 flare (SIDC Flare 7777) peaking at 01:04 UTC on May 25, associated with SIDC Sunspot Group 875 (NOAA Active Region 4447, magnetic type beta). There are currently eleven numbered active regions on the solar disk. The most complex ones have a beta magnetic configuration. SIDC Sunspot Group 870 (NOAA Active Region 4381, magnetic type beta) is currently rotating across the west limb. SIDC Sunspot Groups 878 and 879 (both with magnetic type alpha) have emerged in the northeast quadrant. SIDC Sunspot Group 876 (magnetic type alpha) has rotated on disk from the east limb, in the southeast quadrant. The solar flaring activity is expected to be low to moderate over the next 24 hours, with C-class flares very likely and a chance for M-class probable.

Coronal mass ejections

A Coronal Mass Ejection (SIDC CME 657) was observed in LASCO/C2 coronagraph imagery, lifting off from the northeast limb starting from 07:12 UTC on May 25. It is likely associated with eruptive activity near the northeast limb and it is not expected to impact Earth. No other Earth-directed CMEs were observed in the available coronagraph imagery during the last 24 hours.

Coronal holes

A southern, negative polarity coronal hole (SIDC Coronal Hole 149) is crossing the central meridian. A mild high-speed stream may arrive at Earth starting from May 28.

Solar wind

Over the last 24 hours, the solar wind parameters (ACE and DSCOVR) reflected slow solar wind conditions. The solar wind speed increased from 280 km/s to 360 km/s. The interplanetary magnetic was between 5 nT and 9 nT. The Bz component varied between -7 nT and 4 nT. The interplanetary magnetic field angle phi was predominantly in the negative sector until 23:15 UTC on May 24, when it flipped to mostly positive values. Slow solar wind conditions are expected over the next 24 hours.

Geomagnetism

Geomagnetic conditions globally were mostly quiet (NOAA Kp 1-2) during the last 24 hours, with an interval of unsettled conditions (NOAA Kp 3-) between 00:00 UTC and 03:00 UTC on May 25. Geomagnetic conditions locally were quiet to unsettled (K Bel 2 to 3) during the last 24 hours. Mostly quiet conditions are expected over the next 24 hours.

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 was above the 1000 pfu threshold until 01:35 UTC on May 25, when it decreased to background levels. The greater than 2 MeV electron flux measured by GOES 19 was above the 1000 pfu threshold until 20:45 UTC on May 24, when it decreased to background levels. The 24-hour electron fluence was at moderate levels but it is expected to decrease to normal levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 113, based on 25 stations.

Solar indices for 24 May 2026

Wolf number Catania	///
10cm solar flux	133
AK Chambon La Forêt	014
AK Wingst	008
Estimated Ap	006
Estimated international sunspot number	116 - Based on 27 stations

Noticeable events summary

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

All times in UTC

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