Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 15, 2025 at 07:35 UT. Active region table to be updated

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 unsettled to minor storm levels on June 14 under the influence of effects from CH1301. Solar wind speed at SOHO ranged between 406 and 594 km/sec, averaging 485 km/sec (+61 km/sec compared to the previous day). The high latitude magnetometer at Andenes recorded unsettled to major 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 150.8 - increasing 32.6 over the previous solar rotation. The 365 day average solar flux at 1 AU was 188.01 (183 days ago). SC25 365d peak: 195.86 on October 13, 2024. The Potsdam WDC planetary A index was 25 (STAR Ap - based on the mean of three hour interval ap indices: 24.6). Three hour interval K indices: 55333333 (planetary), 44342333 (Boulder), 65334345 (Andenes).

The background x-ray flux is at the class C2 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 11 active regions using 2K resolution (SN: 285) and in 11 active regions using 1K resolution (SN: 203) SDO/HMI images.

AR 14105 [S15W77] decayed further. The region became more unstable as AR S11161 emerged immediately to the north. C1 flares: C1.3 @ 00:16, C1.5 @ 00:39, C1.4 @ 01:36, C1.8 @ 20:16 UT
AR 14110 [N05W57] developed further and gained a magnetic delta structure in the intermediate spot section. An M flare is possible. C1 flares: C1.9 @ 04:35, C1.7 @ 07:48, C1.9 @ 10:53 UT
AR 14111 [N14E01] gained a few tiny spots and has polarity intermixing.
AR 14112 [S08W18] decayed slowly and quietly and could soon become spotless.
AR 14113 [N10E19] was mostly quiet and stable.
AR 14114 [N18E27] developed further and gained magnetic delta configurations. A major flare is possible. C1 flares: C1.9 @ 01:07, C1.3 @ 02:07, C1.8 @ 06:14 UT
AR 14115 [N20E50] was mostly quiet and stable.
New AR 14116 [S11E25] emerged on June 12 and was numbered by SWPC 2 days later as slow development persisted.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
New region S11160 [S14E12] emerged with tiny spots before noon, then decayed slowly after noon.
New region S11161 [S12W76] emerged immediately to the north of AR 14105 and developed fairly quickly.
New region S11162 [N21E49] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C5.0 02:43   14114 GOES18  
C2.8 03:07   14105 GOES18  
C2.3 05:30   14114 GOES18  
C2.2 05:36   14114 GOES18  
C3.3 08:54   14105 GOES18  
C2.1 10:07   14114 GOES18 simultaneous flare in AR 14105
C2.1 11:30   14114 GOES18  
C2.4 11:58   14116 GOES18  
C2.3 12:44   14105 GOES18  
C2.7 13:28 N23E43 14115 GOES18  
C4.3 14:46   14105 GOES18  
C4.9 15:02   14114 GOES18  
C2.5 16:09   14114 GOES18  
C2.3 16:36   14110 GOES18  
C3.4 17:12   14105 GOES18  
M1.0 18:04   14105 GOES18  
C4.3 19:04   14113 GOES18  
C8.3 21:37   14114 GOES18  
C4.4 22:10   14113 GOES18  
M6.8/1N 23:01   14105 GOES18  

Coronal mass ejections (CMEs)

June 12-14: No obviously Earth directed CMEs.

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 large recurrent positive polarity southern hemisphere coronal hole (CH1301) will be Earth facing on June 11-19.

Forecast

The geomagnetic field is expected to be at quiet to minor storm levels on June 15-23 due to effects associated with CH1301.

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
14105 2025.06.02
2025.06.03
13 23 9 S15W59 0270 EKI EAO

was AR S11119

area: 0290

location: S15W60

14107 2025.06.05
2025.06.06
4     S15W80 0170 DAO       was AR S11129

location: S19W82

spotless

SWPC location on June 9: S18W31. On June 10 SWPC moved this region to the spots of AR S11145

14109 2025.06.05
2025.06.07
  5   S17W46 0007   BXO was AR S11131

location: S17W41

S11138 2025.06.07       S03W42            
14111 2025.06.08
2025.06.09
2 10 4 N14E13 0100 HSX CSO was AR S11139

area: 0160

loction: N14E14

14110 2025.06.08
2025.06.09
13 32 19 N05W44 0080 DAI EAI beta-gamma

was AR S11140

area: 0160

14112 2025.06.08 4 11 4 S09W05 0010 BXO DRO was AR S11141

area: 0030

location: S08W05

S11142 2025.06.08       S24W57            
S11143 2025.06.08       S22W35            
S11145 2025.06.09   4 3 S15W79 0200   DAC

this became AR 14107 to SWPC on 2025.06.10

S11146 2025.06.09       N03W53            
S11148 2025.06.10       N20W23          
14113 2025.06.10
2025.06.11
1 4 1 N10E32 0030 HSX CAO was AR S11149

location: N10E33

area: 0060

14114 2025.06.10
2025.06.11
14 29 20 N18E39 0080 DAI DAI beta-gamma

was AR S11150

area: 0290

14115 2025.06.11
2025.06.12
3 9 4 N21E53 0150 DSO ESO was AR S11151

location: N20E50

area: 0240

S11152 2025.06.11       N15W13            
S11153 2025.06.11       S34W21            
S11154 2025.06.11       S32W39            
S11155 2025.06.11       N04W08            
S11157 2025.06.12   11 9 S11E39 0070   DRI  
S11158 2025.06.12       S07E17          
S11159 2025.06.13   1   S02E46 0002   AXX    
Total spot count: 54 139 73  
Sunspot number: 134 249 163  (total spot count + 10 * number of spotted regions)
Weighted SN: 94 180 114  (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): 147 137 130  

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
2025.06 132.3 (1)   43.9 (2A) / 101.3 (2B) / 122.3 (2C) (114.4 projected, -4.9) (33.2)
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.