Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2026 Jun 16 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
16 Jun 2026	118	019
17 Jun 2026	118	010
18 Jun 2026	118	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 has been low with only C-class flares observed in the last 24 hours. SIDC Sunspot Group 870 (NOAA Active Region 4465) currently located at N09W24 has evolved into a beta-gamma magnetic field configuration. The largest flare was a C1.8 flare (SIDC Flare 7945) peaking on June 15 at 13:15 UTC, which was produced by SIDC Sunspot Group 870 (NOAA Active Regions 4441, 4465). More C-class flares can be expected in the next 24 hours.

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.

Solar wind

The Earth remains within a slow solar wind stream, with speeds hovering around 410 km/s and an interplanetary magnetic field (IMF) of 5 nT. A fast solar wind stream originating from SIDC Coronal Hole 168 is anticipated to arrive within the next 24 hours; however, due to the coronal hole's limited size, any impact is expected to be mild. While the arrival of an ICME related to the June 12 CME remains possible, the probability is currently low.

Geomagnetism

Geomagnetic conditions were quiet at planetary and local levels (Kp and K_Bel up to 2). The possible arrival of a mild high speed stream and the CME from 12 June 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 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): 081, based on 14 stations.

Solar indices for 15 Jun 2026

Wolf number Catania	074
10cm solar flux	117
AK Chambon La Forêt	010
AK Wingst	006
Estimated Ap	004
Estimated international sunspot number	074 - Based on 20 stations

Noticeable events summary

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