Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 17, 2025 at 07:50 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 minor storm levels on July 16 under the influence of effects associated with CH1306. Solar wind speed at SOHO ranged between 489 and 690 km/sec, averaging 571 km/sec (-90 km/sec compared to the previous day). The high latitude magnetometer at Andenes recorded quiet 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 152.1 - increasing 15.9 over the previous solar rotation. The 365 day average solar flux at 1 AU was 182.38 (183 days ago). The 81 day average solar flux at 1 AU was 136.7 (41 days ago, this is 42.8% 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: 195.86 on October 13, 2024. The Potsdam WDC planetary A index was 18 (STAR Ap - based on the mean of three hour interval ap indices: 18.1). Three hour interval K indices: 33332135 (planetary), 33242224 (Boulder), 55342246 (Andenes).

The background x-ray flux is at the class C1 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 15 active regions using 2K resolution (SN: 357) and in 12 active regions using 1K resolution (SN: 233) SDO/HMI images.

AR 14135 [S08W52] was quiet and stable.
AR 14136 [N20W22] developed slowly as new flux emerged. M class flaring is possible.
AR 14138 [N27W84] decayed further nearly losing the few remaining trailing spots.
AR 14139 [N21W40] was mostly quiet and stable. C1 flares: C1.2 @ 10:11 UT
AR 14140 [S17E07] decayed slowly and quietly.
AR 14142 [N01E22] gained spots and area and is still a trans equatorial spot group. M class flaring is possible. C1 flares: C1.3 @ 07:50, C1.2 @ 14:17, C1.5 @ 14:38, C1.6 @ 15:29, C1.7 @ 17:52, C1.8 @ 17:58, C1.8 @ 18:32, C1.4 @ 20:15, C1.5 @ 23:31, C1.7 @ 23:55 UT
AR 14143 [N24W12] developed significantly and has M class flare potential. C1 flares: C1.5 @ 02:47, C1.2 @ 03:29, C1.0 @ 05:17, C1.3 @ 05:33, C1.2 @ 06:02, C1.4 @ 06:11, C1.3 @ 07:20, C1.1 @ 08:48, C1.1 @ 09:56, C1.1 @ 13:10 UT
AR 14144 [S15E48] was quiet and stable.
AR 14145 [S25E07] developed slowly and was mostly quiet. C1 flares: C1.6 @ 21:11 UT
New AR 14147 [N06E55] rotated into view on July 14 and was noticed by SWPC two days later as the region continued to decay slowly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S11237 [S04W24] was quiet and stable.
S11247 [N28W20] reemerged with a tiny spot.
S11259 [S08W01] developed slowly and quietly.
New AR S11261 [S02W54] emerged with a tiny spot.
New AR S11262 [N10E32] emerged with a tiny spot.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.9/1F 00:55 N05E35 14142 GOES18  
C5.0 03:58 N25E03 14143 GOES18  
C2.5 19:04 N02E25 14142 GOES18  
C2.3 21:27   14142 GOES18  

Coronal mass ejections (CMEs)

July 14-16: 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 huge recurrent trans equatorial positive polarity coronal hole (CH1306) was Earth facing on July 8-16. A recurrent negative polarity coronal hole (CH1307) in the northern hemisphere and with a likely trans equatorial extension, will likely rotate across the central meridian on July 19-21.

Forecast

The geomagnetic field is expected to be quiet to active levels on July 17 due to effects from CH1306. Quiet to unsettled levels are likely on July 18-19.

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
14135 2025.07.06
2025.07.07
1 2 1 S09W52 0040 HSX HSX was AR S11226

area: 0090

location: S08W52

14136 2025.07.08
2025.07.09
7 30 18 N19W28 0250 CKO EKC beta-gamma

was AR S11232

location: N20W22

area: 0530

SWPC location is way off

S11236 2025.07.09       N11W44          
S11237 2025.07.09   1   S04W24 0002   AXX  
14138 2025.07.10
2025.07.11
6 3 1 N29W79 0050 CSO CSO

was AR S11240

area: 0170

location: N27W84

14140 2025.07.10
2025.07.11
5 23 8 S15E04 0030 CAO CRO

was AR S11242

location: S17E07

14139 2025.07.11
2025.07.11
11 19 10 N22W42 0250 DKO DKO

beta-gamma

was AR S11243

area: 0520

location: N21W40

S11247 2025.07.12   1 1 N28W21 0003   AXX    
S11249 2025.07.13       N30W57            
S11251 2025.07.13       S09W15            
14142 2025.07.13
2025.07.14
18 45 27 N01E21 0100 DAI EAC beta-gamma-delta

was AR S11252

area: 0480

location: N01E22

14143 2025.07.14
2025.07.14
15 40 26 N23W12 0090 DAI EKC beta-gamma

was AR S11254

area: 0470

location: N24W12

14144 2025.07.14
2025.07.15
1 1 1 S15E48 0030 HSX HSX was AR S11255

area: 0060

14147 2025.07.14
2025.07.16
2 2 2 N06E52 0020 CAO HRX was AR S11256

location: N06E55

S11257 2025.07.14       N08W22            
14145 2025.07.14
2025.07.15
5 19 13 S26E07 0030 CRO DRI was AR S11258

location: S25E07

area: 0060

S11259 2025.07.15   9 5 S08W01 0030   CRI  
S11260 2025.07.15       S13E59          
14146 2025.07.16 1     N18W34 0010 HRX       apparently a misinterpretation by SWPC. Split off the leader spot of AR 14136. Currently there is no reason to do that and the result is inflating the spot number by 10.
S11261 2025.07.16   1   S02W54 0001   AXX    
S11262 2025.07.16   1   N10E32 0002   AXX    
Total spot count: 72 207 113  
Sunspot number: 182 357 233  (total spot count + 10 * number of spotted regions)
Weighted SN: 133 269 175  (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): 200 196 186  

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
2024.10 221.0 219.6 165.8 160.9 (+1.5) (SC25 solar max) 18.99
2024.11 199.6 195.3 154.1 157.1 (-3.8) 9.33
2024.12 197.3 191.2 154.6 151.3 (-5.8) 8.42
2025.01 190.3 184.2 137.0 (146.1 projected, -5.2) 13.17
2025.02  184.2 179.7 155.7 (138.3 projected, -7.8) 14.42
2025.03 163.7 162.1 134.2 (131.9 projected, -6.4) 15.96
2025.04 162.5 163.6 140.6 (127.3 projected, -4.6) 17.62
2025.05  135.3 138.3 79.2 (122.0 projected, -5.3) 17.26
2025.06 131.3 135.4 116.3 (117.1 projected, -4.9) 21.43
2025.07 127.4 (1)   56.8 (2A) / 110.1 (2B) / 133.6 (2C) (112.9 projected, -4.2) (14.0)
2025.08       (108.1 projected, -4.8)  
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 (365 day smoothed peaks: STAR 1K: 236.1, STAR 2K: 364.3, NOAA SN: 156.0, ISN: 163.9). 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.