Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 12, 2026 at 05:45 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 minor storm levels. Solar wind speed at SOHO ranged between 369 and 517 km/sec, averaging 415 km/sec (+23 km/sec compared to the previous day). A high speed stream associated with CH1373 was observed arriving at ACE near 15h UT. 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 127.4 - increasing 26.4 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 140.26 (183 days ago). The 81 day average solar flux at 1 AU was 129.0 (41 days ago, this is 37.9% 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 18 (STAR Ap - based on the average of three hour interval ap indices: 17.6). Three hour interval K indices: 12333254 (planetary), 13343344 (Boulder), 22333255 (Andenes).

The background x-ray flux is at the class B6 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 8 active regions using 2K resolution (SN: 181) and in 7 active regions using 1K resolution (SN: 116) SDO/HMI images.

AR 14462 [N15W49] decayed slowly and quietly.
AR 14463 [N17W14] was quiet and stable.
AR 14464 [S12W18] decayed slowly and quietly.
AR 14465 [N08E30] gained tiny and small spots and has polarity intermixing. Some area was lost though and the region could be in slow decay. C1 flares: C1.0 @ 04:41, C1.5 @ 08:07, C1.1 @ 17:14, C1.5 @ 21:39 UT
AR 14466 [N06W45] was mostly quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S12131 [S03E40] was quiet and stable.
New AR S12136 [S15W13] emerged before noon just south of AR 14464 and developed fairly quickly.
New AR S12137 [S10W20] emerged north of and close to the leader spot of AR 14464.

AR S12116 behind the northwest limb produced a few C1 flares: C1.2 @ 06:47, C1.3 @ 11:36, C1.0 @ 20:32 UT
C1.1 flares were recorded at 07:28 and 20:18 UT from a location behind the southeast limb. A C1.6 flare occurred at 22:20 as well as a C1.2 flare at 23:55 UT. The source active region is rotating into view early on June 12.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C6.2 00:44 behind northwest limb S12116 GOES18  
C9.0 08:28   14465 GOES18  

Coronal mass ejections (CMEs)

June 9-10: No obviously Earth directed CMEs were observed in available coronagraph imagery.
June 11: A full halo CME was observed early in the day following a C6.5 long duration event in AR 14465. The CME could reach Earth on June 13.

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 negative polarity trans equatorial coronal hole (CH1373) was in an Earth facing position on June 9-10.

Forecast

The geomagnetic field is expected to be at quiet to minor storm levels on June 12-13 due to effects from CH1373. The June 11 CME could reach Earth on June 13 and cause active to major storm conditions that day and on June 14.

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
14459 2026.05.31
2026.06.01
      N14W70        

was AR S12110

location: N15W66

14461 2026.06.01       S21W51         was AR S12112

location: S22W46

14462 2026.06.02
2026.06.02
5 14 6 N15W50 0020 DRO DRI

was AR S12115

location: N15W49

14463 2026.06.04
2026.06.05
2 3 1 N17W15 0060 HSX HSX was AR S12117

area: 0080

location: N17W14

S12119 2026.06.04       N20W51            
14464 2026.06.04
2026.06.06
8 18 9 S12W16 0120 DSI DSO was AR S12120

area: 0240

location: S12W18

S12121 2026.06.06       N18W19            
14466 2026.06.06
2026.06.09
6 13 6 N06W47 0030 CRO DRI was AR S12122

location: N06W45

S12124 2026.06.07       S06W55            
14465 2026.06.07
2026.06.08
10 34 16 N09E30 0255 DHI DAI beta-gamma

was AR S12125

area: 0310

location: N08E30

S12127 2026.06.09       S07W20            
S12128 2026.06.09       S43W28            
S12129 2026.06.09       N05W20            
S12130 2026.06.09       N32W37            
S12131 2026.06.09   4   S03E40 0005   BXO  
S12133 2026.06.10       N11W02          
S12134 2026.06.10       S12E68          
S12135 2026.06.10       S17W05          
S12136 2026.06.11   13 7 S15W13 0110   DAO    
S12137 2026.06.11   2 1 S10W20 0010   CRO    
Total spot count: 31 101 46  
Sunspot number: 81 181 116  (total spot count + 10 * number of spotted regions)
Weighted SN: 57 130 75  (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): 89 100 93  

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) 9.8
2026.06 136.1 (1)   47.3 (2A) / 129.0 (2B) / 123.1 (2C) (86.6 projected, -2.1) (12.0)
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.