Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 23, 2026 at 08:25 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 (June 1, 2026)
Solar cycle Solar cycles 23-25 (June 1, 2026) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (June 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 (June 1, 2026) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (June 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 325 and 379 km/sec, averaging 351 km/sec (-22 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 was at background levels all day.

Solar flux density measured at 20h UT on 2.8 GHz was 121.5 - decreasing 19.3 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 139.55 (183 days ago). The 81 day average solar flux at 1 AU was 125.7 (41 days ago, this is 35.8% 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 5 (STAR Ap - based on the average of three hour interval ap indices: 4.6). Three hour interval K indices: 11011122 (planetary), 11122222 (Boulder), 21022123 (Andenes).

The background x-ray flux is at the class B7 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 12 active regions using 2K resolution (SN: 212) and in 10 active regions using 1K resolution (SN: 144) SDO/HMI images.

AR 14470 [N07E02] decayed slowly and quietly.
AR 14472 [S13E28] decayed slowly and quietly.
AR 14473 [S09E39] decayed further and was mostly quiet as the magnetic delta configuration disintegrated.
New AR 14474 [N03W78] emerged on June 20 and was numbered by SWPC 2 days later.
New AR 14475 [S08E48] rotated into view on June 20 with SWPC grouping the region with AR 14473 until June 22. The region decayed slowly and was mostly quiet. C1 flares: C1.2 @ 01:30 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S12141 [S03W48] was quiet and stable.
AR S12147 [N18W25] decayed slowly and quietly.
New AR S12165 [N08E23] emerged with many tiny and small spots.
New AR S12166 [S24E13] was observed with tiny spots in an old plage area before noon and faded a little towards the end of the day.
New AR S12167 [S08E33] was observed with tiny spots in an old plage area.
New AR S12168 [S12E78] rotated into view with a tiny spot.
New AR S12169 [N15W07] was observed with tiny spots in an old plage area.

A C1.4 long duration event was observed peaking at 04:55 UT, its source was behind the southeast limb.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment

Coronal mass ejections (CMEs)

June 20-22: 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 southern hemisphere negative polarity coronal hole (CH1377) will rotate across the central meridian on June 21-23. A trans equatorial negative polarity coronal hole (CH1378) will likely become Earth facing on June 23-24. A recurrent northern hemisphere negative polarity coronal hole (CH1379) will likely become Earth facing on June 24-25.

Forecast

The geomagnetic field is expected to be at quiet levels on June 23. Effects associated with CH1377 could cause quiet to active conditions on June 24-25. CH1378 could cause quiet to minor storm conditions on June 26-27 with effects associated with CH1379 becoming noticable June 27-28.

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
14469 2026.06.10       S16W78           was AR S12134

location: S16W71

14468 2026.06.13
2026.06.14
      N11W72           was AR S12138

location: N11W66

S12141 2026.06.13   4 1 S03W48 0005   AXX  
14471 2026.06.14
2026.06.18
      N17W44         was AR S12144

location: N18W42

S12147 2026.06.14   4   N18W25 0004   AXX  
S12148 2026.06.14       S14W37            
14470 2026.06.15
2026.06.16
6 12 7 N07W12 0015 DRO CRI was AR S12149

area: 0025

S12151 2026.06.16       S17W57            
S12152 2026.06.16       N13W39            
S12154 2026.06.17       N11W09            
S12155 2026.06.18       N16W59            
14472 2026.06.18
2026.06.19
9 21 10 S14E28 0060 DAO CAI was AR S12157

location: S13E28

S12158 2026.06.18       S14W07            
S12159 2026.06.18       S02W38            
14473 2026.06.19
2026.06.20
7 13 8 S09E39 0070 DAI CRI

was AR S12160

location: S09E40

14474 2026.06.20
2026.06.22
4 2 2 N03W75 0040 CAO CAO was AR S12161

location: N03W78

14475 2026.06.20
2026.06.22
5 15 5 S09E51 0130 CAO CKO was AR S12162

area: 0300

location: S08E48

S12163 2026.06.20       N13W23            
S12164 2026.06.21       N37W06          
S12165 2026.06.22   12 7 N08E23 0050   DRI    
S12166 2026.06.22   2   S24E13 0003   AXX    
S12167 2026.06.22   4 2 S08E33 0010   AXX    
S12168 2026.06.22   1 1 S12E78 0005   HRX    
S12169 2026.06.22   2 1 N15W07 0003   AXX    
Total spot count: 31 92 44  
Sunspot number: 81 212 144  (total spot count + 10 * number of spotted regions)
Weighted SN: 54 125 77  (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): 89 117 115  

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
2025.03 163.7 162.1 134.2 135.9 (-3.9) 15.96
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
2025.07 137.8 142.3 125.9 122.4 (-2.3) 11.80
2025.08 154.9 158.7 133.7 118.2 (-4.2) 9.97
2025.09 154.4 156.0 129.7 112.9 (-5.3) 14.02
2025.10 139.5 138.6 114.6 108.3 (-4.6) 15.64
2025.11 140.3 137.3 91.7 106.7 (-1.6) 21.01
2025.12 160.8 155.8 124.0 (106.4 projected, -0.3) 13.35
2026.01 148.7 144.0 112.6 (102.7 projected, -3.7) 22.47
2026.02 136.4 133.1 78.2 (98.5 projected, -4.2) 12.88
2026.03 131.0 129.7 85.9 (93.9 projected, -4.6) 15.44
2026.04  120.0 120.9 79.3 (90.0 projected, -3.9) 12.10
2026.05 125.4 128.2 101.4 (88.7 projected, -1.3) 9.80
2026.06 126.3 (1)   70.2 (2A) / 95.7 (2B) / 122.2 (2C)
ISN preliminary average: 101.5
At this level SSN for December 2025
will become 107.1
(86.6 projected, -2.1) (9.4)
2026.07       (82.2 projected, -4.4)  
2026.08       (80.1 projected, -2.1)  
2026.09       (79.1 projected, -1.0)  
2026.10       (77.1 projected, -2.0)  
2026.11       (74.3 projected, -2.8)  

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.