Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 9, 2025 at 07:25 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, 2025)
Solar cycle Solar cycles 23-25 (June 1, 2025) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (June 1, 2025) 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, 2025) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (June 1, 2025) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (April 21, 2025) Cycle 25 spots (final update December 25, 2019)
  Solar cycles 24-25 transition using 365d smoothing Research: Solar Cycle 25 Started on November 17, 2019 with 365 Days Smoothing
Calculating the Strength of Solar Cycle 25 Using 365-day Smoothing

Recent activity

The geomagnetic field was at quiet to active levels on June 8 under the influence of effects associated with CH1299. Solar wind speed at SOHO ranged between 405 and 477 km/sec, averaging 433 km/sec (+18 km/sec compared to the previous day). The high latitude magnetometer at Andenes recorded 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 115.0 - decreasing 0.5 over the previous solar rotation. The 365 day average solar flux at 1 AU was 188.58 (183 days ago). SC25 365d peak: 195.86 on October 13, 2024. The Potsdam WDC planetary A index was 13 (STAR Ap - based on the mean of three hour interval ap indices: 13.4). Three hour interval K indices: 22223434 (planetary), 22223434 (Boulder), 32334535 (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 15 active regions using 2K resolution (SN: 263) and in 8 active regions using 1K resolution (SN: 129) SDO/HMI images.

AR 14105 [S15E07] decayed slowly producing several low level C flares. C1 flares: C1.2 @ 02:18, C1.9 @ 04:27, C1.0 @ 12:50, C1.9 @ 13:03, C1.3 @ 13:29, C1.7 @ 13:59 UT
AR 14106 [N14W39] decayed slowly and quietly.
AR 14107 [S18W16] decayed slowly and quietly.
AR 14108 [S20W19] decayed slowly and quietly.
AR 14109 [S16E22] displayed signs of decay after noon and was mostly quiet.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S11116 [N10W21] was quiet and stable.
S11120 [N15E09] decayed slowly and quietly.
S11128 [S01W23] decayed slowly and quietly.
S11136 [N25W08] was quiet and stable.
S11138 [S03E23] was quiet and stable.
New region S11139 [N14E80] rotated into view with mature spots.
New region S11140 [N05E26] emerged with tiny spots.
New region S11141 [S04E58] was observed with tiny spots in an old plage area.
New region S11142 [S24E08] emerged with tiny spots.
New region S11143 [S22E30] emerged with tiny spots.

AR 14100 behind the northwest limb produced a C1.0 flare at 01:26 UT.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment

Coronal mass ejections (CMEs)

June 7-8: No obviously Earth directed CMEs.
June 9: A filament eruption from just north of AR 14105 and stretching well into the northeast quadrant was observed beginning early iin the day and peaking near 08h UT. A partial halo CME was seen in LASCO imagery, components of the CME could reach Earth on June 12-13.

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 negative polarity southern hemisphere coronal hole (CH1299) was Earth facing on June 2-5. A small negative polarity northern hemisphere coronal hole (CH1300) rotated across the central meridian on June 8 and extended southward across the equator after a filament eruption. A large recurrent positive polarity southern hemisphere coronal hole (CH1301) will likely become Earth facing on June 12-14.

Forecast

The geomagnetic field is expected to be at quiet to active levels on June 9 due to effects associated with CH1299. Quiet to unsettled is likely on June 10. June 11-12 could see a disturbance related to CH1300 and some unsettled and active intervals. On June 12-13 effects from the June 8 CME could reach Earth and cause unsettled to minor storm levels.

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
14104 2025.05.29
2025.05.30
      N06W87          

was AR S11107

location: N08W80

S11113 2025.05.31       S12W58            
S11114 2025.05.31       N11W38            
S11115 2025.06.01       S11W45          
S11116 2025.06.01   6 2 N10W21 0010   BXO  
14105 2025.06.02
2025.06.03
27 52 26 S15E09 0090 EAI DAI beta-gamma

was AR S11119

area: 0150

location: S15E07

S11120 2025.06.02   4   N15E09 0007   AXX  
14106 2025.06.03
2025.06.04
1 2   N13W41 0010 AXX AXX was AR S11123

area: 0004

location: N14W39

S11124 2025.06.03       N19W56            
S11126 2025.06.04       S16W47            
S11128 2025.06.05   1   S01W23 0002   AXX  
14107 2025.06.05
2025.06.06
3 10 4 S18W15 0020 CRO BXO was AR S11129

location: S18W16

S11130 2025.06.05       S12W13            
14109 2025.06.05
2025.06.07
5 14 7 S16E26 0020 CRO CRI was AR S11131

location: S16E22

area: 0050

14108 2025.06.06
2025.06.07
1 2 1 S22W33 0010 AXX BXO was AR S11133

area: 0004

location: S20W32

S11134 2025.06.06       N36W27            
S11135 2025.06.06       S14W08            
S11136 2025.06.07   1   N25W08 0002   AXX  
S11137 2025.06.07       N12W55          
S11138 2025.06.07   2   S03E23 0003   AXX  
S11139 2025.06.08   2 2 N14E80 0220   HAX    
S11140 2025.06.08   11 6 N05E26 0040   CRI    
S11141 2025.06.08   2   S04E58 0003   AXX    
S11142 2025.06.08   2   S24E08 0004   BXO    
S11143 2025.06.08   2 1 S22E30 0005   BXO    
Total spot count: 37 113 49  
Sunspot number: 87 263 129  (total spot count + 10 * number of spotted regions)
Weighted SN: 48 129 65  (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): 96 145 103  

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2024.01 164.6 159.3 126.0 131.2 (+1.7) 5.46
2024.02 172.5 168.3 123.0 136.9 (+5.7) 5.31
2024.03 154.4 152.9 103.7 141.4 (+4.5) 11.03
2024.04 161.3 162.6 137.0 144.5 (+3.1) 9.69
2024.05 187.7 191.9 172.1 149.1 (+4.6) 23.56
(SC25 peak)
2024.06 184.3 190.2 164.1 152.8 (+3.7) 10.24
2024.07 196.6 203.0 196.8 155.0 (+2.3) 7.13
2024.08  246.1
(cycle peak)
252.2 216.0  (SC25 peak) 156.8 (+1.8) 15.96
2024.09 195.7 197.8 141.1 159.4 (+1.6) 15.36
2024.10 221.0 219.6 165.8 160.8 (+1.4) (SC25 solar max) 18.99
2024.11 199.6 195.3 154.1 157.0 (-3.8) 9.33
2024.12 197.3 191.2 154.6 (150.7 projected, -6.3) 8.42
2025.01 190.3 184.2 137.0 (144.2 projected, -6.5) 13.17
2025.02  184.2 179.7 154.6 (135.6 projected, -8.6) 14.42
2025.03 163.7 162.1 134.2 (129.2 projected, -6.4) 15.96
2025.04 162.5 163.6 140.6 (124.6 projected, -4.6) 17.62
2025.05  135.3 138.3 79.2 (119.3 projected, -5.3) 17.26
2025.06 130.5 (1)   24.8 (2A) / 93.1 (2B) / 111.9 (2C) (114.4 projected, -4.9) (37.2)
2025.07       (110.2 projected, -4.2)  
2025.08       (105.5 projected, -4.7)  
2025.09       (101.2 projected, -4.3)  
2025.10       (97.3 projected, -3.9)  
2025.11       (95.0 projected, -2.3)  

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 May 13, 2025

Sunspot activity has been on a slowly decreasing trend since September 2024 (using the average solar flux over 3 solar rotations as a proxy). The decline has become more obvious during the first half of May 2025 with solar flux on May 12 at its lowest level since April 4, 2024. The solar max phase of solar cycle 25 was considerably shorter than that of the most recent solar cycles.

All 365 days smoothed sunspot numbers peaked on October 11-12, 2024
, very likely making this the peak of SC25 (STAR 1K 365d peak: 236.1, STAR 2K 365d peak: 364.3, NOAA SN 365d peak: 156.0, ISN 365d peak: 163.6). 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.