Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 19, 2026 at 07:55 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. Solar wind speed at SOHO ranged between 350 and 441 km/sec, averaging 387 km/sec (-54 km/sec compared to the previous day). The high latitude magnetometer at Andenes was at quiet to active 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 110.7 - decreasing 13.7 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 139.69 (183 days ago). The 81 day average solar flux at 1 AU was 126.9 (41 days ago, this is 36.6% 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: 5.6). Three hour interval K indices: 21111123 (planetary), 22112312 (Boulder), 33022434 (Andenes).

The background x-ray flux is at the class B4 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 14 active regions using 2K resolution (SN: 235) and in 9 active regions using 1K resolution (SN: 120) SDO/HMI images.

AR 14465 [N08W62] decayed slowly and was mostly quiet.
AR 14469 [S17W20] was quiet and stable.
AR 14470 [N07E42] was mostly quiet and stable. C1 flares: C1.0 @ 07:46, C1.8 @ 11:50 UT
New AR 14471 [N18E11] was first observed with spots on June 14. New flux emerged on June 17 and the region was numbered the next day by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S12131 [S03W51] reemerged with tiny spots.
AR S12141 [S04W01] was quiet and stable.
AR S12145 [N04W15] reemerged with a tiny spot.
AR S12147 [N17E29] reemerged with tiny spots. C1 flares: C1.2 @ 22:04 UT
AR S12151 [S17W05] was quiet and stable.
New AR S12155 [N21W03] was observed with tiny spots in an old plage area.
New AR S12156 [N11W31] emerged with a tiny spot.
New AR S12157 [S14E81] rotated into view with a few spots.
New AR S12158 [S14E45] emerged with a tiny spot.
New AR S12159 [S02E14] emerged with a tiny spot.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.0 11:56   14470 GOES18  

Coronal mass ejections (CMEs)

June 16-18: 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]

An elongated trans equatorial positive polarity coronal hole (CH1376) was Earth facing on June 15-18, slowly closing over the last days. A recurrent negative polarity coronal hole (CH1377) will likely rotate across the central meridian on June 21-22.

Forecast

The geomagnetic field is expected to be at quiet to unsettled levels on June 19-21 due to effects associated with CH1376 and quiet on June 22-23. Effects associated with CH1377 could cause quiet to unsettled conditions on June 24-25.

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
14465 2026.06.07
2026.06.08
5 7 4 N07W62 0090 CSO CSO

was AR S12125

area: 0150

S12131 2026.06.09   1   S03W51 0001   AXX    
14469 2026.06.10   8 1 S16W22 0010   BXO was AR S12134

location: S17W20

14468 2026.06.13
2026.06.14
      N11W17           was AR S12138

location: N11W14

S12139 2026.06.13       N20W41          
S12141 2026.06.13   22 5 S04W01 0030   BXO  
14471 2026.06.14
2026.06.18
5 16 6 N18E11 0030 DAO DAO  
S12145 2026.06.14   1   N04W15 0002   AXX    
S12146 2026.06.14       S27W26            
S12147 2026.06.14   10 2 N17E29 0020   BXO    
S12148 2026.06.14       S14E02            
14470 2026.06.15
2026.06.16
6 13 7 N07E40 0070 DAO DAO was AR S12149

area: 0130

location: N07E42

S12150 2026.06.15       S01W35            
S12151 2026.06.16   2 1 S17W05 0004   BXO  
S12152 2026.06.16       N13E13            
S12154 2026.06.17       N11E30          
S12155 2026.06.18   8   N21W03 0010   BXO    
S12156 2026.06.18   1 1 N11W31 0002   AXX    
S12157 2026.06.18   4 3 S14E81 0150   CAO    
S12158 2026.06.18   1   S14E45 0002   AXX    
S12159 2026.06.18   1   S02E14 0002   AXX    
Total spot count: 16 95 30  
Sunspot number: 46 235 120  (total spot count + 10 * number of spotted regions)
Weighted SN: 31 115 50  (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): 51 129 96  

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
2026.06 128.7 (1)   61.5 (2A) / 102.4 (2B) / 126.1 (2C) (86.6 projected, -2.1) (10.3)
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.