Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 28, 2026 at 09:15 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 (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 to unsettled levels under the decreasing influence of effects associated with CH1378. Solar wind speed at SOHO ranged between 473 and 893 km/sec, averaging 595 km/sec (-42 km/sec compared to the previous day). The high latitude magnetometer at Andenes was at quiet to minor storm 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 187.9 - increasing 52.3 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 140.06 (183 days ago). The 81 day average solar flux at 1 AU was 128.1 (41 days ago, this is 37.3% 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 6 (STAR Ap - based on the average of three hour interval ap indices: 5.8). Three hour interval K indices: 32111112 (planetary), 33212222 (Boulder), 53212233 (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 11 active regions using 2K resolution (SN: 315) and in 9 active regions using 1K resolution (SN: 193) SDO/HMI images.

AR 14472 [S13W39] decayed slowly and quietly.
AR 14475 [S09W21] gained new spots to the north of the main penumbrae and has polarity intermixing in a fairly compact configuration. The spot group was the most active flare produced of the day. C1 flares: C1.7 @ 00:39, C1.5 @ 13:22, C1.4 @ 17:12 UT
AR 14476 [N08W44] decayed slowly and quietly.
AR 14477 [S13E15] decayed slowly and quietly.
AR 14478 [S05E33] appears to have lost the magnetic delta configuration. There's still significant polarity intermixing and a major flare is possible. C1 flares: C1.6 @ 02:06, C1.9 @ 02:59, C1.4 @ 17:50 UT
AR 14479 [N16E17] developed slowly and produced low level C flares. C1 flares: C1.8 @ 14:14, C1.9 @ 15:16, C1.5 @ 16:02 UT
New AR 14480 [S18E09] emerged on June 26 and developed fairly quickly the next day when it was numbered by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
New AR S12176 [S13E09] emerged before noon with several spots, and decayed slowly late in the day.
New AR S12177 [S02E26] emerged before noon and decayed slowly after noon.
New AR S12178 [N00E17] emerged before noon at the equator.
New AR S12179 [N25W08] emerged with a tiny spot.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.1 05:03   14478 GOES18  
C2.4 05:41   14478 GOES18  
C2.3 06:26 S04E43 14478 GOES18  
C2.0 06:38   14478 GOES18  
C2.1 06:54 S11W14 14475 GOES18  
C2.2 07:27 S04E40 14478 GOES18  
C2.1 08:35   14478 GOES18  
C2.4 08:45   14480 GOES18  
C3.9 09:23 S10W18 14475 GOES18  
C3.7 09:36   14475 GOES18  
C2.5 09:53   14479 GOES18  
C2.1 11:53   14478 GOES18  
C2.9 12:21 S06W15 14475 GOES18  
C2.3 18:43   14475 GOES18  
C4.3 20:24   14475 GOES18  
C7.4 21:02 S05W20 14475 GOES18  
C7.4 21:11   14475 GOES18  

Coronal mass ejections (CMEs)

June 25-27: 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 trans equatorial negative polarity coronal hole (CH1378) was Earth facing on June 23-24. A recurrent northern hemisphere negative polarity coronal hole (CH1379) was Earth facing on June 24-25. A northern hemisphere positive polarity coronal hole (CH1380) developed on June 27 close to the central meridian.

Forecast

The geomagnetic field is expected to be at quiet levels on June 28-30. There is a slight chance of unsettled and active intervals on June 30 should effects from CH1380 arrive then.

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
14470 2026.06.15
2026.06.16
      N08W78           was AR S12149
14472 2026.06.18
2026.06.19
  5   S15W40 0005   AXX was AR S12157

location: S13W39

14473 2026.06.19
2026.06.20
      S07W34          

was AR S12160

location: S08W25

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

14475 2026.06.20
2026.06.22
17 40 21 S10W19 0150 DAI DAI was AR S12162

area: 0190

location: S09W21

14476 2026.06.22
2026.06.23
2 5 1 N08W44 0010 AXX CRO

was AR S12165

S12166 2026.06.22       S24W52            
S12167 2026.06.22       S07W31          
14477 2026.06.22
2026.06.23
7 28 14 S15E13 0010 BXO BXI was AR S12168

area: 0040

location: S13E15

14478 2026.06.23
2026.06.24
24 61 34 S06E33 1190 FKC FKC beta-gamma

was AR S12170

area: 1930

location: S05E33

14479 2026.06.23
2026.06.24
5 28 16 N15E16 0090 DAI DAO was AR S12171

area: 0350

location: N16E17

S12172 2026.06.24       S05E08            
S12173 2026.06.24       N09W54            
S12174 2026.06.25       N10W23            
14480 2026.06.26
2026.06.27
4 20 12 S18E07 0030 DAO DAI was AR S12175

area: 0180

location: S18E09

S12176 2026.06.27   8 3 S13E09 0015   BXO    
S12177 2026.06.27   7 1 S02E20 0008   BXO    
S12178 2026.06.27   2 1 N00E17 0003   AXX    
S12179 2026.06.27   1   N25W08 0002   AXX    
Total spot count: 59 205 103  
Sunspot number: 119 315 193  (total spot count + 10 * number of spotted regions)
Weighted SN: 84 233 131  (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): 131 173 154  

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
2026.06 131.6 (1)   89.7 (2A) / 99.7 (2B) / 115.4 (2C)
ISN preliminary average to date: 102.1
At this level SSN for December 2025
will become 107.1
(86.6 projected, -2.1) (9.9)
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.