Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 1, 2026 at 10:25 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 (August 1, 2026) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (August 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 (August 1, 2026) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (August 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 levels. Solar wind speed at SOHO ranged between 308 and 364 km/sec, averaging 324 km/sec (-27 km/sec compared to the previous day). The high latitude magnetometer at Andenes was at quiet to unsettled levels. The above 10 MeV proton flux fluctuated throughout the day peaking at 17:6 pfu at 15:55 UT and ending the UT day at 4 pfu. A surge in proton levels is possible when the July 30 CME reaches Earth.

Solar flux density measured at 20h UT on 2.8 GHz was 147.6 - decreasing 13.0 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 140.36 (183 days ago). The 81 day average solar flux at 1 AU was 136.9 (41 days ago, this is 42.9% 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 4 (STAR Ap - based on the average of three hour interval ap indices: 3.9). Three hour interval K indices: 11112111 (planetary), 11113422 (Boulder), 32112313 (Andenes).

The background x-ray flux is at the class B8 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 16 active regions using 2K resolution (SN: 297) and in 12 active regions using 1K resolution (SN: 188) SDO/HMI images.

AR 14492 [N16W86] rotated partly out of view and was quiet.
AR 14494 [S03W69] decayed slowly and quietly.
AR 14496 [N05W36] was mostly quiet and stable.
AR 14498 [N14E24] regained a small magnetic delta in the trailing spots. A major flare is possible in conjunction with AR 14500. C1 flares: C1.7 @ 19:50, C1.8 @ 20:13, C1.2 @ 20:39 UT
AR 14499 [N03W08] lost the magnetic delta observed the previous day and gained a smaller magnetic delta in the intermediate spot section. Most of the flares of the day had their origin in this spot group. C1 flares: C1.8 @ 05:33, C1.6 @ 07:27, C1.4 @ 08:33, C1.3 @ 10:11, C1.7 @ 13:57, C1.6 @ 18:12 UT
AR 14500 [N17E28] appeared to decay slightly as the region continued to approach the northeastern spots of AR 14498. C1 flares: C1.4 @ 00:22, C1.8 @ 01:29 UT
AR 14501 [S07W14] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S12445 [N04W26] reemerged with tiny spots.
AR S12448 [N06W20] was quiet and stable.
AR S12256 [S14E21] was quiet and stable.
AR S12257 [N09E46] decayed slowly and quietly.
New AR S12259 [N17W73] emerged with tiny spots.
New AR S12260 [S06E31] emerged with tiny spots.
New AR S12261 [N06E17] emerged with tiny spots.
New AR S12262 [N04E18] emerged with tiny spots and an east-west inversion line.
New AR S12263 [N31E15] emerged with tiny spots.

C1 flares not attributed to an AR due to missing imagery: C1.8 @ 07:07 UT

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.3 02:39   14499 GOES18  
C3.1 03:16   14498 GOES18  
C2.5 03:54   14498 GOES18  
C2.2 04:46   14499 GOES18  
C2.3 04:53   14499 GOES18 simultaneous flare in AR 14500
C2.2 06:10   14499 GOES18  
C2.4 06:47 N05E00 14499 GOES18  
C2.2 06:57     GOES18  
C2.3/1F 11:19 N06W00 14499 GOES18  
C2.5 11:41   14499 GOES18  
C4.0 11:47   14499 GOES18  

Coronal mass ejections (CMEs)

July 29, 31: No obviously Earth directed CMEs were observed in available coronagraph imagery.
July 30: A full halo CME was observed after the M1.9 LDE in AR 14492. The CME could reach Earth late on August 1 or sometime on August 2.

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]

No obvious coronal holes are currently in or near Earth facing locations.

Forecast

The geomagnetic field is expected to be at quiet levels initially on August 1. Late in the day or on August 2 the July 30 CME is expected to arrive and cause active to major storm conditions. Quiet levels are likely on August 3-4.

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
14492 2026.07.18
2026.07.19
2 2 2 N15W88 0110 HAX HKX was AR S12227

area: 0270

location: N16W86

14497 2026.07.20
2026.07.26
      S21W88         was AR S12230
14494 2026.07.20
2026.07.21
1 2 1 S05W70 0010 AXX AXX was AR S12231

location: S03W69

14495 2026.07.22
2026.07.23
1     S04W83 0010 AXX     was AR S12241

spotless

location: S02W82

14496 2026.07.22
2026.07.23
4 8 4 N05W37 0110 CSO DSO was AR S12242

area: 0170

location: N05W36

S12245 2026.07.24   2   N04W26 0003   BXO    
S12246 2026.07.25       S23W51            
S12247 2026.07.25       N18W49            
S12248 2026.07.26   2   N06W20 0003   AXX  
14498 2026.07.27
2026.07.27
8 27 13 N14E22 0150 DAI DHC beta-gamma-delta

was AR S12449

area: 0370

14499 2026.07.27
2026.07.28
12 32 16 N05W08 0080 DAO DAI beta-delta

was AR S12250

location: N03W08

S12251 2026.07.27       N07W51            
14500 2026.07.28
2026.07.29
7 21 10 N18E28 0050 CAO DAO was AR S12252

area: 0180

location: N17E28

14501 2026.07.28
2026.07.29
8 16 11 S08W12 0040 CAO DAO

 

was AR S12253

area: 0230

location: S07W14

S12254 2026.07.28       N21E21            
S12255 2026.07.28       N14W11          
S12256 2026.07.29   10 3 S14E21 0025   BXO  
S12257 2026.07.30   1   N09E46 0002   AXX  
S12258 2026.07.30       N19E07          
S12259 2026.07.31   3 1 N17W73 0010   CRO    
S12260 2026.07.31   4 3 S06E31 0015   DRO    
S12261 2026.07.31   2 2 N06E17 0012   DRO    
S12262 2026.07.31   3 2 N04E18 0006   BXO    
S12263 2026.07.31   2   N31E15 0003   BXO    
Total spot count: 43 137 68  
Sunspot number: 123 297 188  (total spot count + 10 * number of spotted regions)
Weighted SN: 73 186 117  (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): 135 163 150  

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
2025.05 135.3 138.3 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
2026.01 148.7 144.0 115.0 104.2 (-2.8) 22.47
2026.02 136.4 133.1 77.4 (99.7 projected, -4.5) 12.88
2026.03 131.0 129.7 86.6 (94.6 projected, -5.1) 15.44
2026.04  120.0 120.9 79.3 (90.7 projected, -3.9) 12.10
2026.05 125.4 128.2 101.4 (89.5 projected, -1.2) 9.80
2026.06 137.9 142.2 94.3 (87.4 projected, -2.1) 9.57
2026.07 134.7 139.0 78.1 (82.8 projected, -4.6) 10.3
2026.08 (1)   (2A/2B) / 96.4 (2C) (80.6 projected, -2.2) ()
2026.09       (79.7 projected, -0.9)  
2026.10       (77.7 projected, -2.0)  
2026.11       (74.8 projected, -2.9)  
2026.12       (71.6 projected, -3.2)  
2027.01       (69.3 projected, -2.3)  

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.

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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.