Viewing archive of Tuesday, 26 May 2026

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2026 May 26 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
26 May 2026	141	008
27 May 2026	143	010
28 May 2026	145	022

Solar Active Regions and flaring

Solar flaring activity has been low over the last 24 hours, with few C-class flares. The strongest flare was C4.7 flare (SIDC Flare 7781) peaking at 23:59 UTC on May 25, from beyond the east limb. There are currently twelve numbered active regions on the solar disk. The most complex ones have a beta magnetic configuration. SIDC Sunspot Group 870 (NOAA Active Region 4381) has rotated behind the west limb. SIDC Sunspot Group 878 has decayed into plage. SIDC Sunspot Group 880 (NOAA Active Region 4450, magnetic type beta) has emerged in the northeast quadrant. SIDC Sunspot Groups 881 and 882 (both with magnetic type beta) have emerged in the northwest quadrant. The solar flaring activity is expected to be low over the next 24 hours, with C-class flares very likely and a chance for M-class flares.

Coronal mass ejections

A partial halo Coronal Mass Ejection (SIDC CME 658) was observed in LASCO/C2, LASCO/C3 and STEREO-A coronagraph imagery, starting from 22:30 UTC on May 25, lifting off from the west limb. The bulk of the ejecta propagates to the northwest, with an estimated projected speed of around 1250km/s. It is most likely a backsided event and it is not expected to impact Earth. SIDC CME 659 was observed in LASCO/C2 and STEREO-A coronagraph imagery, starting from 04:42 UTC on May 26, lifting off from the southeast limb. It is likely associated with eruptive activity near SIDC Sunspot Group 873 (NOAA Active Region 4446) 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

The southern, negative polarity coronal hole (SIDC Coronal Hole 149) is crossing the central meridian since May 25.

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 350 km/s to 400 km/s. The interplanetary magnetic was initially between 1 nT and 9 nT and then decreased to around 5 nT. The Bz component varied between -6 nT and 5 nT. The interplanetary magnetic field angle phi was predominantly in the negative sector. 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 21:00 UTC on May 25 and 00:00 UTC on May 26. 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 above the 10 pfu threshold between 00:10 UTC and 04:30 UTC on May 26. It is expected to further decrease to nominal levels over the next 24 hours.

Electron fluxes at geostationary orbit

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

Today's estimated international sunspot number (ISN): 150, based on 20 stations.

Solar indices for 25 May 2026

Wolf number Catania	167
10cm solar flux	139
AK Chambon La Forêt	015
AK Wingst	012
Estimated Ap	012
Estimated international sunspot number	115 - Based on 34 stations

Noticeable events summary

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

All times in UTC

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