Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 1, 2025 at 05:15 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  

Recent activity

The geomagnetic field was at quiet to unsettled levels on June 30. Solar wind speed at SOHO ranged between 437 and 524 km/sec, averaging 485 km/sec (-30 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 128.2 - decreasing 6.6 over the previous solar rotation. The 365 day average solar flux at 1 AU was 185.38 (183 days ago). The 81 day average solar flux at 1 AU was 142.5 (41 days ago, this is 46.4% of the 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: 195.86 on October 13, 2024. The Potsdam WDC planetary A index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 10.6). Three hour interval K indices: 22231333 (planetary), 33242332 (Boulder), 43332445 (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 16 active regions using 2K resolution (SN: 299) and in 13 active regions using 1K resolution (SN: 196) SDO/HMI images.

AR 14121 [S10W73] decayed slowly and quietly.
AR 14122 [N12W12] decayed slowly and was mostly quiet. C1 flares: C1.2 @ 06:33 UT
AR 14123 [S28W23] was mostly quiet and stable.
AR 14124 [S15E10] was quiet and stable.
AR 14125 [N21E35] was quiet and stable.
AR 14126 [N07W53] was quiet and stable.
AR 14127 [S18E18] displayed signs of decay and was quiet.
AR 14128 [S05E28] was mostly quiet and stable. C1 flares: C1.0 @ 03:56 UT
New AR 14129 [N01E37] emerged on June 28 and was numbered by SWPC 2 days later as slow development continued. The region has polarity intermixing. C1 flare: C1.1 @ 17:00 UT.
New AR 14130 [S10E70] rotated into view with tiny spots. Normally small spots like these are not observed this close to the limb by SWPC. The larger spots further south were not noticed despite being at the same longitude. C1 flares: C1.2 @ 12:56, C1.4 @ 13:27, C1.0 @ 15:20, C1.1 @ 18:05, C1.9 @ 18:34 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S11187 [N13W40] decayed slowly and quietly.
S11207 [S09E37] decayed slowly and quietly.
S11209 [S17E70] was mostly quiet and stable.
New AR S11212 [N08W00] emerged after noon with several tiny spots.
New AR S11213 [N11E78] rotated into view with tiny spots.
New AR S11214 [S18W52] emerged with tiny spots.

AR 14118 produced a few C1 flares while at or near the southwest limb: C1.0 @ 11:33, C1.0 @ 11:46 UT

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment

Coronal mass ejections (CMEs)

June 29-30: No obviously Earth directed CMEs.
June 28: A partial halo CME was observed late in the day and may have been associated with a C4 flare in AR 14126. The CME could reach Earth late on June 1 or early on June 2.

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 southern hemisphere coronal hole (CH1304) will rotate into an Earth facing position on June 29 - July 4.

Forecast

The geomagnetic field is expected to be at quiet to unsettled levels on July 1. July 2-4 could see quiet to active levels due to effects from CH1304 and the June 28 CME.

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
14118 2025.06.17
2025.06.19
5     S13W88 0010 BXO    

was AR S11170

rotated out of view

14120 2025.06.22
2025.06.23
2     N06W93 0050 CSO     was AR S11183

rotated out of view

14121 2025.06.22
2025.06.23
  1   S11W73 0001   AXX was AR S11184

location: S10W73

S11187 2025.06.23   6   N13W40 0010   BXO  
14122 2025.06.23
2025.06.25
11 27 11 N12W11 0080 DSO DSO was AR S11188

area: 0200

location: N12W12

14126 2025.06.24
2025.06.28
1 5 4 N08W56 0005 AXX CRO was AR S11190

location: N07W53

area: 0020

S11193 2025.06.25       S14W31            
S11197 2025.06.26       S31W48            
14124 2025.06.26
2025.06.27
2 7 4 S14E10 0010 BXO CRO

was AR S11198

location: S15E10

area: 0025

14125 2025.06.26
2025.06.27
1 6 1 N21E32 0040 HSX CSO was AR S11199

area: 0100

location: N21E35

14123 2025.06.26
2025.06.27
5 17 11 S28W23 0030 CRO DRI was AR S11200

area: 0070

S11201 2025.06.26       S13W53          
14128 2025.06.27
2025.06.29
5 11 7 S04E26 0040 DAO DAO was AR S11202

area: 0140

location: S05E28

14127 2025.06.27
2025.06.29
7 18 8 S18E20 0030 CRO DRI was AR S11203

area: 0080

location: S18E18

S11205 2025.06.28       S30W26           merged with AR 14123 on 2025.06.29
14129 2025.06.28
2025.06.30
8 20 11 N02E38 0030 CRI DAI beta-gamma

was AR S11206

location: N01E37

area: 0080

S11207 2025.06.29   3 1 S09E37 0007   BXO  
S11208 2025.06.29       N17E13          
S11209 2025.06.29   2 2 S17E70 0040   HRX  
S11210 2025.06.29       N25E38          
14130 2025.06.30
2025.06.30
1 2 1 S12E68 0005 AXX BXO   was AR S11211

location: S10E70

S11212 2025.06.30   8 4 N08W00 0025   DRO    
S11213 2025.06.30   2   N11E78 0002   AXX    
S11214 2025.06.30   4 1 S18W52 0006   BXO    
Total spot count: 48 139 66  
Sunspot number: 158 299 196  (total spot count + 10 * number of spotted regions)
Weighted SN: 77 177 104  (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): 174 164 157  

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
2025.06 131.3 135.4 106.9 (2A/2B) / 133.9 (2C)
ISN average to date: 112.8.
At this level the SSN for
December 2024 will become 151.0
(114.4 projected, -4.9) 21.2
2025.07 (1)     (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 June 23, 2025

Sunspot activity has been on a decreasing trend since September 2024 (using the average solar flux over 3 solar rotations as a proxy). Compared to the peak of SC25 solar flux has been at a low level in both May and June 2025. Taking a closer look at the 81 day (3 solar rotations) average solar flux proxy, its peak was in early September 2024 and had on May 12 decreased to less than half of the solar cycle flux range. Subtracting the 81 day average of approximately 69 at solar cycle minimum from all measurements, the SC25 range is 0 - 158.3.

All 365 day 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.