Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 24, 2026 at 11:15 UT.

Charts (* = updated daily) Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data since 2003.01 (July 1, 2026)
Solar cycle Solar cycles 23-25 (July 1, 2026) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (July 1, 2026) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (August 1, 2020) POES auroral activity level [October 2009 - December 2012]
  Comparison of cycles 21-25 (July 1, 2026) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (July 1, 2026) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (December 21, 2025) Cycle 25 initial spots (final update December 25, 2019)
  Solar cycles 24-25 transition using 365d smoothing  

Recent activity

The geomagnetic field was at quiet to major storm levels under the influence of effects associated with CH1387. Solar wind speed at SOHO ranged between 440 and 747 km/sec, averaging 609 km/sec (+179 km/sec compared to the previous day). The high latitude magnetometer at Andenes was at unsettled to major storm levels. The above 10 MeV proton flux was at background levels.

Solar flux density measured at 20h UT on 2.8 GHz was 147.6 - decreasing 15.1 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 140.38 (183 days ago). The 81 day average solar flux at 1 AU was 134.4 (41 days ago, this is 41.3% of the total SC25 solar flux range from the max 81 day average peak on September 4, 2024 at 227.3 and an average 81 day flux of 69 at solar minimum). SC25 365d peak: 195.9 on October 13, 2024.

The Potsdam WDC planetary A index was 24 (STAR Ap - based on the average of three hour interval ap indices: 24.1). Three hour interval K indices: 22333563 (planetary), 32343533 (Boulder), 43334564 (Andenes).

The background x-ray flux is at the class C1 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 12 active regions using 2K resolution (SN: 243) and in 9 active regions using 1K resolution (SN: 142) SDO/HMI images.

AR 14489 [S07W66] was quiet and stable.
AR 14491 [S13W25] regained a trailing polarity spot and was quiet.
AR 14492 [N15E19] was mostly quiet and stable. C1 flares: C1.0 @ 10:40 UT
AR 14493 [N05W30] elongated and lost most of the intermediate spots as well as the magnetic delta. Flare frequency and intensity decreased further. C1 flares: C1.1 @ 00:44, C1.2 @ 01:41, C1.7 @ 02:53, C1.5 @ 03:12, C1.2 @ 05:17, C1.0 @ 06:31, C1.0 @ 08:30, C1.2 @ 16:46, C1.9 @ 16:52 UT
AR 14494 [S03E39] developed and gained a magnetic delta configuration in the largest penumbra. M flares are possible. C1 flares: C1.4 @ 03:46, C1.1 @ 05:25, C1.3 @ 06:44, C1.3 @ 10:02, C1.1 @ 13:12, C1.5 @ 16:06, C1.2 @ 17:33 UT
New AR 14495 [S02E28] emerged on July 22 and was numbered by SWPC the next day as the region began to decay.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S12224 [S16W04] was quiet and stable.
AR S12232 [S08W07] was mostly quiet and stable. C1 flares: C1.7 @ 04:29 UT
AR S12235 [S22E15] reemerged with tiny spots.
AR S12239 [S17E27] was quiet and stable.
AR S12242 [N05E72] was quiet and stable.
New AR S12243 [S05W13] emerged with a tiny spot.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.0 03:18   14493 GOES18  
C5.3 03:27 N07W17 14493 GOES18  
C2.8 15:12   S12242 GOES18  

Coronal mass ejections (CMEs)

July 21-23: No obviously Earth directed CMEs were observed in available coronagraph imagery.

Coronal holes

[Coronal hole history (since October 2002)]
[Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago]

A recurrent trans equatorial negative polarity coronal hole (CH1387) was Earth facing on July 20-21. The area of CH1387 was severely reduced on July 20-21 due to the expansion of AR 14493.

Forecast

The geomagnetic field is expected to be at quiet to active levels on July 24 due to effects associated with CH1387. Quiet conditions are likely on July 25-26.

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)
     

1) Effects from a coronal hole could reach Earth within the next 5 days. When the high speed stream has arrived the color changes to green.
2) Effects from a CME are likely to be observed at Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48 hours.

Green: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% probability.

Active solar regions



(Click on image for 2K resolution). 4K resolution. Compare to the previous day's image.
0.5K image

When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue is positive.

Data for all officially numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC, all other regions are numbered sequentially as they emerge using the STAR spot number. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers. SWPC data considered to be not sufficiently precise (location, area, classification) are colored red.

Active region SWPC date numbered
STAR detected
Spot count Location at midnight Area Classification SDO / HMI 4K continuum
image with magnetic polarity overlays
Comment
SWPC/
USAF
STAR SWPC STAR Current Previous
2K 1K
14489 2026.07.12
2026.07.13
2 3 2 S07W67 0050 HSX CAO

was AR S12215

area: 0090

location: S07W66

14490 2026.07.14
2026.07.13
      N15W82           was AR S12216

location: N16W75

14491 2026.07.15
2026.07.16
  5 1 S11W34 0010   BXO was AR S12221

location: S13W25

S12223 2026.07.17       S13W43            
S12224 2026.07.17   5 2 S16W04 0010   BXO  
S12226 2026.07.18       N03W48            
14492 2026.07.18
2026.07.19
9 21 8 N16E20 0310 HHX CKO was AR S12227

area: 0560

location: N15E19

14493 2026.07.19
2026.07.20
19 34 22 N06W32 0440 EKI EKI was AR S12229

beta-gamma

area: 0780

location: N05W30

S12230 2026.07.20       S22E24          
14494 2026.07.20
2026.07.21
5 24 8 S04E40 0070 CAO DAC was AR S12231

beta-delta

area: 0160

location: S03E39

S12232 2026.07.20   9 2 S08W07 0015   BXO  
S12233 2026.07.20       N16W55            
S12235 2026.07.20   5   S22E15 0007   BXO    
S12237 2026.07.21       N07E08            
S12238 2026.07.21       N11W34            
S12239 2026.07.21   5   S17E27 0005   BXO  
S12240 2026.07.21       S17W55            
14495 2026.07.22
2026.07.23
3 6 3 S02E28 0010 AXX HRX was AR S12241

area: 0020

S12242 2026.07.22   5 4 N05E72 0080   CAO  
S12243 2026.07.23   1   S05W13 0002   AXX    
Total spot count: 38 123 52  
Sunspot number: 88 243 142  (total spot count + 10 * number of spotted regions)
Weighted SN: 68 161 90  (Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10)
Relative sunspot number (Wolf number): 97 134 114  

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2024.05 187.7 191.9 172.1 149.1 (+4.6) 23.56
(SC25 peak)
2024.08  246.1
(SC25 peak)
252.2 216.0  (SC25 peak) 156.8 (+1.8) 15.96
2024.10 221.0 219.6 165.8 160.9 (+1.5) (SC25 solar max) 18.99
2025.04 162.5 163.6 141.4 133.3 (-2.6) 17.62
2025.05 135.3 138.3 78.5 128.6 (-4.7) 17.26
2025.06 131.3 135.4 114.6 124.7 (-3.9) 21.43
2025.07 137.8 142.3 125.9 122.5 (-2.2) 11.80
2025.08 154.9 158.7 133.7 118.4 (-4.1) 9.97
2025.09 154.4 156.0 129.7 113.1 (-5.3) 14.02
2025.10 139.5 138.6 114.6 108.5 (-4.6) 15.64
2025.11 140.3 137.3 91.7 106.9 (-1.6) 21.01
2025.12 160.8 155.8 124.0 107.0 (-0.1) 13.35
2026.01 148.7 144.0 115.0 (104.4 projected, -2.6) 22.47
2026.02 136.4 133.1 77.4 (100.0 projected, -4.4) 12.88
2026.03 131.0 129.7 86.6 (94.7 projected, -5.3) 15.44
2026.04  120.0 120.9 79.3 (90.8 projected, -3.9) 12.10
2026.05 125.4 128.2 101.4 (89.5 projected, -1.3) 9.80
2026.06 137.9 142.2 94.3 (87.4 projected, -2.1) 9.57
2026.07 130.4 (1)   50.5 (2A) / 71.1 (2B) / 98.6 (2C)
Average ISN to date: 76.2
At this level the SSN for January
2026 would become: 104.1
(82.9 projected, -4.5) (12.1)
2026.08       (80.7 projected, -2.2)  
2026.09       (79.8 projected, -0.9)  
2026.10       (77.7 projected, -2.1)  
2026.11       (74.9 projected, -2.8)  
2026.12       (71.7 projected, -3.2)  

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz and any corrections applied to that measurement.
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days).
2B) Boulder SN current month average to date.
2C) STAR SDO 1K Wolf number 27 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international GFZ Potsdam WDC ap indices.
4) Source: WDC-SILSO, Royal Observatory Of Belgium, Brussels

Solar cycles 24-25

Smoothed SF and sunspot numbers

Update on the progress of solar cycle 25 as of March 2026

Solar activity appears to have exited the solar max phase as of February 2026 with a strong decrease in the number of sunspots observed. The northern polar field has weakened considerably over the last months, and although there is a chance the the field could recover over the next 1-2 years, there is an increasing chance that solar cycle 26 will be very weak. The southern polar field is not impressive either, however, a southern polar coronal hole has formed early in 2026 and appears to be growing.

All 365 day smoothed sunspot numbers reached a maximum on October 11-12, 2024
. This became the peak of SC25 (365 day smoothed peaks: STAR 1K: 236.1, STAR 2K: 364.3, NOAA SN: 156.0, ISN: 163.9), while the 365d smoothed solar flux peaked on October 13, 2024, just 1.7% below the SC23 peak, and 62.6% above the SC24 peak.

--------------------------------------------------------------------------------------

This report has been prepared by Jan Alvestad. It is based on the analysis of data from whichever sources are available at the time the report is prepared. All time references are to Universal Time. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.