Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 4, 2025 at 07:45 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 (July 1, 2025)
Solar cycle Solar cycles 23-25 (July 1, 2025) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (July 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 (July 1, 2025) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (July 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 active levels on July 3 under the influence of CIR effects associated with CH1304. Solar wind speed at SOHO ranged between 338 and 404 km/sec, averaging 375 km/sec (+3 km/sec compared to the previous day). Solar wind density, which had been on an increasing trend since late on July 1, peaked near 10h UT. The phi angle was in a negative sector after 11:30 UT. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. The above 10 MeV proton flux was at background most of the day with a very weak increase noted towards the end of the day.

Solar flux density measured at 20h UT on 2.8 GHz was 125.1 - increasing 0.6 over the previous solar rotation. The 365 day average solar flux at 1 AU was 185.04 (183 days ago). The 81 day average solar flux at 1 AU was 141.2 (41 days ago, this is 45.6% 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 14 (STAR Ap - based on the mean of three hour interval ap indices: 14.5). Three hour interval K indices: 33334223 (planetary), 24343324 (Boulder), 54234344 (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 17 active regions using 2K resolution (SN: 286) and in 10 active regions using 1K resolution (SN: 155) SDO/HMI images.

AR 14122 [N11W53] gained a few spots to the north of the main penumbra and was mostly quiet. C1 flares: C1.3 @ 02:18, C1.6 @ 10:42 UT
AR 14123 [S28W64] decayed slowly and quietly.
AR 14124 [S15W29] decayed slowly and quietly.
AR 14125 [N21W05] was quiet and stable.
AR 14127 [S18W19] developed slowly and was mostly quiet. C1 flares: C1.0 @ 04:57, C1.9 @ 10:51 (simultaneous flare in AR 14126) UT
AR 14128 [S04W11] decayed slowly and quietly.
AR 14129 [N02W02] developed slowly and was mostly quiet.
AR 14130 [S10E30] reemerged with tiny spots.
AR 14131 [N08W44] decayed slowly and quietly.
AR 14132 [S18E29] was mostly quiet and stable. C1 flares: C1.2 @ 03:57, C1.0 @ 07:26, C1.6 @ 08:51 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S11207 [S09W03] reemerged with tiny spots.
S11213 [N10E37] reemerged with a tiny spot.
S11217 [S19W15] decayed slowly and quietly.
New AR S11218 [N04E41] was observed with tiny spots in an old plage area.
New AR S11219 [S05E54] was observed with a tiny spot in an old plage area.
New AR S11220 [N33E17] was observed with tiny spots in an old plage area.
New AR S11221 [S16E51] emerged with a tiny spot.

AR 14126 produced C1 flares while rotating over the northwest limb: C1.2 @ 01:29, C1.0 @ 01:48, C1.6 @ 02:47, C1.7 @ 03:01, C1.0 @ 06:10, C1.4 @ 08:46, C1.8 @ 09:52, C1.8 @ 10:16 UT

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.0 08:15   14126 GOES18  

Coronal mass ejections (CMEs)

July 1-3: 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 recurrent negative polarity southern hemisphere coronal hole (CH1304) will be in an Earth facing position on June 29 - July 4. CH1304 has decayed over the last few days due to the development of AR 14127 and split into a western and an eastern part on July 3.

Forecast

The geomagnetic field is expected to be at quiet to active levels on July 4-6 due to effects associated with CH1304.

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
14122 2025.06.23
2025.06.25
2 8 3 N12W54 0070 HSX CSO was AR S11188

area: 0170

location: N11W53

14124 2025.06.26
2025.06.27
  2   S14W34 0003   BXO

was AR S11198

location: S15W29

14125 2025.06.26
2025.06.27
1 8 1 N21W08 0040 HSX CSO was AR S11199

area: 0090

location: N21W05

14123 2025.06.26
2025.06.27
2 2 1 S28W66 0030 CRO CRO was AR S11200

area: 0020

location: S28W64

14128 2025.06.27
2025.06.29
3 7 4 S06W14 0030 CRO CRO was AR S11202

area: 0025

location: S04W11

14127 2025.06.27
2025.06.29
16 28 16 S19W22 0080 DAC DAI was AR S11203

area: 0200

location: S18W19

14129 2025.06.28
2025.06.30
10 29 19 N02W04 0030 CRI DRI

was AR S11206

location: N02W02

area: 0100

S11207 2025.06.29   2   S09W03 0003   AXX    
S11208 2025.06.29       N20W25          
14132 2025.06.29
2025.07.01
3 7 4 S17E28 0010 BXO CRO beta-gamma

was AR S11209

location: S18E29

area: 0020

S11210 2025.06.29       N25W01            
14130 2025.06.30
2025.06.30
  9 5 S12E25 0030   CRO   was AR S11211

location: S10E30

14131 2025.06.30
2025.07.01
1 2 1 N08W44 0010 AXX AXX was AR S11212

area: 0005

S11213 2025.06.30   1   N10E37 0001   AXX    
S11215 2025.07.01       S19E01            
S11217 2025.07.02   2 1 S19W15 0005   AXX  
S11218 2025.07.03   5   N04E41 0007   BXO    
S11219 2025.07.03   1   S05E54 0001   AXX    
S11220 2025.07.03   2   N33E17 0003   AXX    
S11221 2025.07.03   1   S16E51 0001   AXX    
Total spot count: 38 116 55  
Sunspot number: 118 286 155  (total spot count + 10 * number of spotted regions)
Weighted SN: 62 146 85  (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): 130 157 124  

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
2024.12 197.3 191.2 154.6 151.2 (-5.8) 8.42
2025.01 190.3 184.2 137.0 (146.0 projected, -5.2) 13.17
2025.02  184.2 179.7 154.6 (138.2 projected, -7.8) 14.42
2025.03 163.7 162.1 134.2 (131.8 projected, -6.4) 15.96
2025.04 162.5 163.6 140.6 (127.2 projected, -4.6) 17.62
2025.05  135.3 138.3 79.2 (121.9 projected, -5.3) 17.26
2025.06 131.3 135.4 116.3 (117.0 projected, -4.9) 21.43
2025.07 126.9 (1)   13.2 (2A) / 136.7 (2B) / 134.8 (2C) (112.8 projected, -4.2) (8.9)
2025.08       (108.1 projected, -4.7)  
2025.09       (103.8 projected, -4.3)  
2025.10       (99.9 projected, -3.9)  
2025.11       (97.6 projected, -2.3)  
2025.12       (96.0 projected, -1.6)  

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.