Sun news: Fast solar wind on its way to Earth

Sun news July 20: Fast solar wind on its way to Earth

Today’s top story: A large coronal hole we saw a couple of weeks ago has passed around the far side of the sun and returned to our star’s Earth-facing side. This “hole” in the sun’s outer atmosphere has just crossed the center of the solar disk. That means the fast solar wind streaming from it is on its way to our planet, and should reach our magnetic field late on July 21. As a result, geomagnetic activity could climb to G1 (minor) geomagnetic storm levels by July 22. Stay tuned!

Past 24 hours on the sun

(11 UTC July 19 – 11 UTC July 20)

Flare activity: Solar activity remained low over the past day. Observers recorded three C-class (common) flares and one B-class (weak) event.

• Strongest flare: A C2.1 from an as-yet unnumbered region at 7:39 UTC on July 20.
• Other flares: A C1.9 occurred at 18:48 UTC on July 19, followed by a C1.3 at 18:25 UTC on July 19. Both came from a region just beyond the southeast limb.
• The three numbered regions on the visible disk stayed largely inactive throughout the period. Instead, action on the horizon accounted for most of the flaring.

Sunspot regions: The Earth-facing solar disk displayed three numbered active regions.

• AR4489 (beta-gamma): The most magnetically complex region on the disk. It sits in the south-central area. During the period, it underwent slight development and an increase in magnetic complexity. Even so, it stayed largely inactive in terms of flare production.
• Meanwhile, forecasters noted a new, unnumbered region in the east. It shows continued growth.
• The remaining numbered regions stayed mostly unchanged and quiet. They contributed no significant flare activity.
• Finally, active regions beyond the southeast limb continued to produce C-class flares. This suggests potentially significant activity may rotate into view in the coming days.

Blasts from the sun? Forecasters cataloged four coronal mass ejections (CMEs) during the period. However, none should impact Earth.

Past 24 hours in space weather

Solar wind: Solar wind conditions remained at background levels throughout the period.

Bt, Bz and magnetic coupling: The interplanetary magnetic field stayed weak. The Bz component fluctuated gently between moderately northward and southward, but the southward dips were not sustained enough to drive geomagnetic activity. These are textbook quiet solar wind conditions: the calm before the coronal hole wind arrives.

Earth’s magnetic field: Earth’s magnetic field stayed quiet throughout the entire period, with Kp values of just 0–2. No geomagnetic storm conditions occurred. Auroras remained confined to the highest latitudes around the auroral oval. Moreover, the short summer nights in the Northern Hemisphere further limited any visibility.

What’s ahead? Sun–Earth forecast

Flare activity forecast: Forecasters expect low levels to continue through July 20–22, though with a slight chance of M-class (moderate) flare activity. The main candidates for any uptick include AR4489, the most magnetically complex region currently on disk with its beta-gamma configuration, plus the new regions rotating onto the northeast disk.

C-class flares are deemed very likely (50% or greater probability), with a smaller chance for M-class events. X-class (strong) flares are not expected at this time.

Geomagnetic activity forecast:

• July 20: Expect quiet conditions to persist under the slow solar wind environment. Kp 0–2 is likely.
• July 21: Anticipate quiet-to-unsettled conditions through most of the day. Late on July 21, a co-rotating interaction region ahead of a negative-polarity coronal hole high-speed stream will likely arrive. This will enhance the solar wind environment. Consequently, unsettled-to-active conditions are expected by late in the day, with a chance for G1 (minor) storm levels near the end of the period. Minor auroral enhancements are possible, perhaps reaching northern Scotland, southern Alaska and similar magnetic latitudes. However, Northern Hemisphere summer twilight will severely limit visual sightings.
• July 22: Expect unsettled-to-active periods, with G1 (minor) geomagnetic storm levels likely. Kp values of 4–5 are possible. If conditions align, aurora may appear over Seattle, Edinburgh, southern Scandinavia and Hobart (Tasmania). Southern Hemisphere observers have the advantage of longer winter nights. Conditions may gradually ease later in the day or into July 23 as the stream wanes.

The sun in recent days

Sun images from our community

We sometimes feature sun images obtained using hydrogen-alpha filters. Read why.

Bottom line: Sun news July 20, 2026: The sun stayed quiet, but a big coronal hole’s fast wind arrives July 21-22. G1 (minor) storms and auroras are possible.

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