Viewing archive of Wednesday, 17 June 2026

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2026 Jun 17 1231 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Quiet

	10cm flux	Ap
17 Jun 2026	113	014
18 Jun 2026	113	007
19 Jun 2026	113	013

Solar Active Regions and flaring

A total of 5 numbered sunspot groups were identified on the disk over the past 24 hours. They all have simple alpha or beta magnetic field configuration, and have only produced minor C-class flaring in the past 24 hours. The largest flare was a C1.2 flare peaking on June 17 at 05:20 UTC, which was produced by SIDC Sunspot Group 870 (NOAA Active Region 4465).

Coronal mass ejections

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

Coronal holes

SIDC Coronal Hole 168 (equatorial coronal hole with a positive polarity) crossed the central meridian on June 13 and is now positioned on the western side of the Sun. SIDC Coronal Hole 169 (equatorial coronal hole with a positive polarity) is currently crossing the central meridian.

Solar wind

The ICME corresponding to the 12 June CME arrived to the Earth early on 17 June. As expected, the effect of the ICME was weak with a magnetic field reaching 12 nT (with Bz mostly positive) and a speed around 415 km/s. The arrival of a fast solar wind stream, from SIDC Coronal Hole 168 could be expected in the next 24 hours; however, due to the coronal hole's limited size, any impact is expected to be mild.

Geomagnetism

Geomagnetic conditions were quiet at planetary levels (Kp up to 2.33) and reached unsettled conditions at local levels (K_Bel up to 3). The possible arrival of a mild high speed stream may increase geomagnetic conditions.

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 slightly above the 1000 pfu alert threshold in the past 24 hours. The flux is expected to fluctuate around the alert threshold 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): 059, based on 17 stations.

Solar indices for 16 Jun 2026

Wolf number Catania	///
10cm solar flux	113
AK Chambon La Forêt	012
AK Wingst	010
Estimated Ap	009
Estimated international sunspot number	079 - Based on 21 stations

Noticeable events summary

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

All times in UTC

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