Viewing archive of Thursday, 18 June 2026

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2026 Jun 18 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
18 Jun 2026	111	007
19 Jun 2026	111	013
20 Jun 2026	111	007

Solar Active Regions and flaring

A total of 4 numbered sunspot groups were identified on the disk over the past 24 hours. Solar activity was low, with only C-class flares visible. The largest flare was a C2.5 flare (SIDC Flare 7960) peaking on June 17 at 15:06 UTC, which was produced by SIDC Sunspot Group 891 (NOAA Active Region 4464). Solar flaring activity is expected to be low over the next 24 hours, with C-class flares likely.

Coronal mass ejections

No Earth-directed CMEs were observed in the last 24 hours.

Coronal holes

SIDC Coronal Hole 169 (equatorial coronal hole with a positive polarity) first reached the central meridian on June 15 and is now positioned on the western side of the Sun.

Solar wind

A mild high speed solar wind stream from SIDC Coronal Hole 168 arrived at the Earth in the last 24 hours, with speeds reaching 520 km/s and magnetic fields of 6 nT. The solar wind speed is back to 400 km/s. In the next 24 hours we may see yet one more mild high speed stream arriving, from SIDC Coronal Hole 169.

Geomagnetism

Geomagnetic conditions were quiet both at planetary and local levels (Kp and K_Bel up to 2). The possible arrival of a mild high speed stream may increase geomagnetic levels.

Proton flux levels

The greater than 10 MeV proton flux, as measured by GOES-18, was below the 10 pfu threshold level over the past 24 hours and is expected to remain so for the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux, as measured by GOES-18 and GOES-19 was below the 1000 pfu alert threshold in the past 24 hours. The flux is expected to remain low over the next 24 hours. The 24-hour electron fluence was at normal levels over the past 24 hours and is expected to remain at these levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 060, based on 19 stations.

Solar indices for 17 Jun 2026

Wolf number Catania	059
10cm solar flux	111
AK Chambon La Forêt	011
AK Wingst	009
Estimated Ap	024
Estimated international sunspot number	059 - Based on 25 stations

Noticeable events summary

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

All times in UTC

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