Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 10, 2026 at 04:05 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. The arrival of a weak CME associated with the June 6 event was recorded at 10:00 UT at SOHO. Solar wind speed at SOHO ranged between 380 and 470 km/sec, averaging 438 km/sec (-34 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 129.5 - increasing 25.7 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 140.32 (183 days ago). The 81 day average solar flux at 1 AU was 128.6 (41 days ago, this is 37.6% 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 12 (STAR Ap - based on the average of three hour interval ap indices: 11.6). Three hour interval K indices: 22223433 (planetary), 22223333 (Boulder), 34224443 (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 13 active regions using 2K resolution (SN: 255) and in 9 active regions using 1K resolution (SN: 154) SDO/HMI images.

AR 14459 [N15W40] decayed slowly and quietly.
AR 14461 [S21W20] was mostly quiet and stable.
AR 14462 [N15W22] decayed slowly and quietly.
AR 14463 [N17E12] was quiet and stable.
AR 14464 [S12E09] decayed quickly, has weak polarity intermixing and many small spots. Several low level C flares were recorded. C1 flares: C1.3 @ 00:40, C1.2 @ 13:02 UT
AR 14465 [N08E57] developed a weak magnetic delta configuration in a small penumbra to the north of the main spot. The region was the source of numerous low level C flares. An M flare is possible. C1 flares: C1.3 @ 01:03, C1.0 @ 01:17, C1.4 @ 02:04, C1.7 @ 02:36, C1.0 @ 03:34, C1.0 @ 04:59, C1.3 @ 05:28, C1.4 @ 05:58, C1.2 @ 08:13, C1.1 @ 08:27, C1.1 @ 08:41, C1.1 @ 09:00, C1.5 @ 09:11, C1.3 @ 09:49, C1.3 @ 13:34, C1.1 @ 15:39, C1.1 @ 15:51, C1.2 @ 16:05, C1.2 @ 16:20, C1.4 @ 20:13, C1.2 @ 23:25 UT
New AR 14466 [N06W17] emerged on June 6 and was noticed by SWPC 3 days later as the region developed slowly. C1 flares: C1.6 @ 19:43, C1.9 @ 21:09, C1.5 @ 22:55 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S12116 [N17W76] decayed further and was mostly quiet.
AR S12119 [N20W25] was quiet and stable.
New AR S12127 [S07E06] emerged with tiny spots.
New AR S12129 [N05E06] emerged with tiny spots.
New AR S12130 [N32W11] emerged with a tiny spot.
New AR S12131 [S03E68] was observed with tiny spots in an old plage area.

A reversed polarity region emerged in the southern hemisphere near noon and was numbered AR S12128. The region decayed after 15h UT and was spotless by the end of the day. Its location at midnight was S43W02.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.5 04:23 N10E66 14465 GOES18  
C2.6 06:06 N10E66 14465 GOES18  
C2.7 06:41 behind NW limb 14455 GOES18  
C3.2 07:00   14465 GOES18  
C2.3/1F 19:18 S21W16 14461 GOES18  
C2.0 21:33   14464 GOES18  

Coronal mass ejections (CMEs)

June 7-9: 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 negative polarity trans equatorial coronal hole (CH1373) will rotate into an Earth facing position on June 9-10.

Forecast

The geomagnetic field is expected to be at quiet to active levels on June 9 due to weak CME effects. A quiet field is likely on June 10-11 with unsettled to minor storm conditions likely on June 12-13 due to effects from CH1373.

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
14456 2026.05.29
2026.05.30
3     N18W73 0060 ESO       was AR S12105

real location: N15W80

spotless

SWPC relocated AR 14456 to AR S12116 on 2026.06.05

SWPC location on 2026.06.04: N14W13

14458 2026.05.30
2026.06.01
1     S06W87 0060 HSX    

was AR S12108

rotated out of view

14459 2026.05.31
2026.06.01
2 7 4 N14W42 0020 HSX HRX

was AR S12110

area: 0030

location: N15W40

14461 2026.06.01   5   S21W23 0005   BXO was AR S12112

location: S21W20

S12114 2026.06.02       N25W48          
14462 2026.06.02
2026.06.02
10 22 14 N15W22 0070 DSI DAI

was AR S12115

area: 0090

S12116 2026.06.04   6 4 N17W76 0030   ERO

see AR 14456

14463 2026.06.04
2026.06.05
1 6 2 N16E10 0070 HSX CSO was AR S12117

area: 0110

location: N17E12

S12119 2026.06.04   4   N20W25 0005   AXX  
14464 2026.06.04
2026.06.06
15 31 18 S12E11 0250 EHI DSI was AR S12120

location: S12E09

S12121 2026.06.06       N18E07            
14466 2026.06.06
2026.06.09
2 21 10 N06W16 0010 BXO DRI was AR S12122

area: 0050

location: N06W17

S12124 2026.06.07       S06W29          
14465 2026.06.07
2026.06.08
6 14 8 N09E54 0220 DSI DKC beta-delta

was AR S12125

area: 0380

location: N08E57

S12127 2026.06.09   4 3 S07E06 0020   DRO    
S12128 2026.06.09       S43W02          
S12129 2026.06.09   2 1 N05E06 0005   AXX    
S12130 2026.06.09   1   N32W11 0001   AXX    
S12131 2026.06.09   2   S03E68 0002   BXO    
Total spot count: 40 125 64  
Sunspot number: 120 255 154  (total spot count + 10 * number of spotted regions)
Weighted SN: 80 162 101  (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): 132 140 123  

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
2026.06 138.4 (1)   40.8 (2A) / 136.0 (2B) / 119.7 (2C) (86.6 projected, -2.1) (11.9)
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.

--------------------------------------------------------------------------------------

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.