Viewing archive of Saturday, 18 July 2026

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2026 Jul 18 1231 UTC

SIDC Forecast

Solar flares

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
18 Jul 2026	104	010
19 Jul 2026	102	006
20 Jul 2026	100	004

Solar Active Regions and flaring

Solar flaring activity has been low over the past 24 hours, with very few C-class flares. The strongest flare was a C2.3 flare (SIDC Flare 8209) peaking at 04:05 UTC on July 18, associated with SIDC Sunspot Group 916 (NOAA Active Region 4489). There are currently three numbered active regions on the solar disk, all with alpha magnetic configuration. SIDC Sunspot Group 910 (NOAA Active Region 4482) has rotated behind the west limb. The solar flaring activity is expected to be very low over the next 24 hours, with a chance for C-class flares.

Coronal mass ejections

A Coronal Mass Ejection (SIDC CME 691) was observed in LASCO/C2 and STEREO-A coronagraph imagery, lifting off from the east limb, starting from around 17:50 UTC on July 17. It is most likely a backsided event that is not expected to impact Earth. No other Earth- directed CMEs were observed in the available coronagraph imagery during the last 24 hours.

Solar wind

Over the past 24 hours, the solar wind parameters (SOLAR-1 and ACE) reflected slow solar wind conditions. The solar wind speed decreased from 370 km/s to 330 km/s. The interplanetary magnetic field was between 3 nT and 5 nT. The Bz component was between -3 nT and 3 nT. The interplanetary magnetic field angle phi was mostly in the positive sector, with short intervals of negative values. Slow solar wind conditions are mostly expected over the next 24 hours, with a small chance for enhanced conditions in case of the late arrival of a mild high-speed stream from the northern, positive polarity coronal hole (SIDC Coronal Hole 174).

Geomagnetism

Geomagnetic conditions globally and locally were mostly quiet (NOAA Kp 1 to 2, K Bel 1 to 2) during the past 24 hours. Mostly quiet to unsettled conditions (NOAA Kp 1 to 3) are expected over the next 24 hours, with a small chance for isolated active intervals (NOAA Kp 4) in case of the late arrival of a mild high-speed stream from the northern, positive polarity coronal hole (SIDC Coronal Hole 174).

Proton flux levels

The greater than 10 MeV proton flux was below the 10 pfu threshold during the past 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 between 17:25 UTC on July 17 and 01:40 UTC on July 18. The greater than 2 MeV electron flux measured by GOES 19 was enhanced, but remained below the 1000 pfu threshold during the past 24 hours. The greater than 2 MeV electron flux is expected to remain mostly below the 1000 pfu threshold over the next 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): 028, based on 13 stations.

Solar indices for 17 Jul 2026

Wolf number Catania	056
10cm solar flux	105
AK Chambon La Forêt	011
AK Wingst	008
Estimated Ap	006
Estimated international sunspot number	037 - Based on 31 stations

Noticeable events summary

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

All times in UTC

<< Go to daily overview page