Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 29, 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 (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 403 and 561 km/sec, averaging 465 km/sec (-132 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 186.1 - increasing 54.2 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 140.24 (183 days ago). The 81 day average solar flux at 1 AU was 129.1 (41 days ago, this is 38.0% 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: 3.8). Three hour interval K indices: 22110001 (planetary), 22121212 (Boulder), 23111123 (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 9 active regions using 2K resolution (SN: 306) and in 7 active regions using 1K resolution (SN: 198) SDO/HMI images.

AR 14475 [S09W35] decayed losing area, however, a magnetic delta configuration formed in the central section and M flares are possible. C1 flares: C1.9 @ 03:10, C1.7 @ 04:04, C1.9 @ 05:51, C1.8 @ 20:30 UT
AR 14476 [N08W57] decayed slowly and quietly.
AR 14477 [S12E01] was mostly quiet and stable.
AR 14478 [S06E20] matured as the intermediate spot section lost spots while the huge leader spot gained area. There is some weak polarity intermixing, however, the region was mostly quiet. A major flare is possible. C1 flares: C1.8 @ 04:27, C1.9 @ 13:54, C1.8 @ 19:29 UT
AR 14479 [N16E03] developed significantly gaining area, spots and complexity as several small magnetic delta configurations formed. A major flare is possible. C1 flares: C1.9 @ 05:15 UT
AR 14480 [S18W04] decayed slowly and was mostly quiet. C1 flares: C1.9 @ 12:57 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
New AR S12180 [N17E35] was observed with tiny spots in an old plage area.
New AR S12181 [N17E14] was observed with tiny spots in an old plage area.
New AR S12182 [S09W83] emerged with a tiny spots near the southwest limb.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.9 00:22   14475 GOES18  
C4.1 01:55   14475 GOES18  
C2.1 04:45   14478 GOES18  
C2.1 04:55   14475 GOES18  
C2.2 05:24   14475 GOES18  
C2.4 06:54   14475 GOES18  
C2.2 07:06   14475 GOES18  
C2.3 08:52   14478 GOES18 simultaneous event in AR 14479
C2.5 09:38   14479 GOES18  
C2.7 09:50   14479 GOES18  
C2.7 10:11   14480 GOES18  
C2.1 12:30   14479 GOES18  
C2.2 14:01   14478 GOES18  
C2.1 14:11   14478 GOES18  
C2.7 15:09   14478 GOES18  
C2.0 15:24   14475 GOES18  
C2.1 17:07   14478 GOES18  
C2.1 18:08   14480 GOES18  
C2.3 18:22   14480 GOES18  
C2.2 19:59   14479 GOES18  
C2.8 20:46   14479 GOES18  
C3.3 20:59   14477 GOES18  
C5.3 21:34   14479 GOES18  
C9.5/1F 21:44 S06W33 14475 GOES18  
C8.7/1F 21:59 N17E09 14479 GOES18  
C8.2 22:03   14479 GOES18  
C2.4 23:42   14479 GOES18  

Coronal mass ejections (CMEs)

June 26-28: 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 northern hemisphere positive polarity coronal hole (CH1380) developed on June 27 close to the central meridian and closed on June 28.

Forecast

The geomagnetic field is expected to be at quiet levels on June 29 - July 1. There is a slight chance of unsettled and active intervals on June 30 or July 1 should effects from CH1380 arrive.

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
14472 2026.06.18
2026.06.19
      S15W54         was AR S12157

location: S13W52

14473 2026.06.19
2026.06.20
      S07W49          

was AR S12160

location: S08W38

SWPC moved this AR to the location of AR S12167 on 2026.06.25

14475 2026.06.20
2026.06.22
17 37 20 S10W33 0110 DAI DAC beta-delta

was AR S12162

area: 0130

location: S09W35

14476 2026.06.22
2026.06.23
1 5 3 N08W58 0010 AXX BXO

was AR S12165

location: N08W57

S12167 2026.06.22       S07W44            
14477 2026.06.22
2026.06.23
6 27 10 S14W00 0010 BXO BXI was AR S12168

area: 0040

location: S12E01

14478 2026.06.23
2026.06.24
27 74 47 S06E20 1140 FKC FKC beta-gamma

was AR S12170

area: 2010

14479 2026.06.23
2026.06.24
11 42 31 N16E02 0160 DAI DKC beta-gamma-delta

was AR S12171

area: 0700

location: N16E03

S12172 2026.06.24       S05W05            
S12174 2026.06.25       N10W36            
14480 2026.06.26
2026.06.27
9 20 15 S18W05 0070 DAO DSO was AR S12175

area: 0110

location: S18W04

S12176 2026.06.27       S13W04          
S12177 2026.06.27       S02E07          
S12178 2026.06.27       N00E04          
S12179 2026.06.27       N25W21          
S12180 2026.06.28   4   N17E35 0005   BXO    
S12181 2026.06.28   6 2 N17E14 0010   BXO    
S12182 2026.06.28   1   S09W83 0001   AXX    
Total spot count: 71 216 128  
Sunspot number: 131 306 198  (total spot count + 10 * number of spotted regions)
Weighted SN: 96 246 158  (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): 144 168 158  

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
2026.06 133.5 (1)   94.1 (2A) / 100.8 (2B) / 114.7 (2C)
ISN preliminary average to date: 103.8
At this level SSN for December 2025
will become 107.2
(86.6 projected, -2.1) (9.7)
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.