Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 26, 2026 at 08:50 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 (January 1, 2026)
Solar cycle Solar cycles 23-25 (January 1, 2026) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (January 1, 2026) 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 (January 1, 2026) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (January 1, 2026) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (December 21, 2025) Cycle 25 initial 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 January 25 under the decreasing influence of effects associated with CH1340. Solar wind speed at SOHO ranged between 470 and 604 km/sec, averaging 537 km/sec (+13 km/sec compared to the previous day). The high latitude magnetometer at Andenes was at active to minor storm levels. The above 10 MeV proton flux decreased very slowly and was near 0.6 pfu at the end of the UT day.

Solar flux density measured at 20h UT on 2.8 GHz was 164.5 - decreasing 31.3 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 151.43 (183 days ago). The 81 day average solar flux at 1 AU was 147.6 (41 days ago, this is 49.6% 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: 195.9 on October 13, 2024.

The Potsdam WDC planetary A index was 15 (STAR Ap - based on the average of three hour interval ap indices: 15.1). Three hour interval K indices: 33333322 (planetary), 33333322 (Boulder), 45444454 (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 17 active regions using 2K resolution (SN: 300) and in 14 active regions using 1K resolution (SN: 200) SDO/HMI images.

AR 14341 [S11W72] decayed slowly and quietly.
AR 14342 [N17W69] decayed slowly and was mostly quiet. Note that SWPC groups AR S11780 with this AR even though the ARs are well separated. C1 flares: C1.7 @ 08:01 UT
AR 14345 [S17W71] decayed slowly and quietly.
AR 14347 [N09W44] was quiet and stable.
AR 14349 [S14W05] decayed slowly and quietly.
AR 14351 [S05W33] gained spots and became more complex. C1 flares: C1.8 @ 05:15, C1.3 @ 06:14, C1.5 @ 08:16, C1.4 @ 14:33 UT
AR 14353 [N17W29] decayed quickly and was mostly quiet.
AR 14354 [S11W31] decayed slowly and quietly.
AR 14355 [S13E32] decayed slightly and was quiet.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S11780 [N10W72] decayed quickly.
AR S11793 [N18W10] decayed slowly and quietly.
AR S11806 [N26E53] was quiet and stable.
AR S11807 [N07W44] was quiet and stable.
AR S11809 [N18E16] was quiet and stable.
AR S11810 [N08E12] was quiet and stable.
New AR S11812 [S11E08] emerged with tiny spots before noon.
New AR S11813 [N17E48] emerged with a tiny spot.

C1 flares not attributed to any ARs due to missing imagery: C1.2 @ 02:05, C1.3 @ 02:37 UT

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.2 03:41   14351 GOES18  
C2.5 04:13   14351 GOES18  
C6.3 10:30   14351 GOES18  
C2.1 11:57   14342 GOES18  
C2.2 12:37   14342 GOES18  
C4.5 15:45   14349 GOES18  
C2.3 17:08   14351 GOES18  
C2.1 17:20   14351 GOES18  
C2.2 17:50   14343 GOES18  
C2.8 20:00   14345 GOES18  
C3.2 20:38   14349 GOES18  
C4.9 21:08   14349 GOES18  
C3.7 21:26   14349 GOES18  
C7.9 21:43   14342 GOES18  
C3.1 22:13   14349 GOES18  
C2.6 23:21   14349 GOES18  

Coronal mass ejections (CMEs)

January 23-25: No obviously Earth directed CMEs were observed in available coronagraph imagery.

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 trans equatorial negative polarity coronal hole (CH1341) rotated across the central meridian on January 24-25.

Forecast

The geomagnetic field is expected to be mostly quiet on January 26. Effects from CH1341 could cause quiet to active levels on January 27-28.

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
14341 2026.01.13
2026.01.14
3 5 2 S10W74 0090 CSO CAO

was AR S11770

location: S11W72

14342 2026.01.14
2026.01.14
3 2 1 N15W72 0140 DSO HAX

was AR S11772

area: 0200

location: N17W71

SWPC includes the spots of AR S11780

14344 2026.01.15       N19W84          

location: N18W79

14345 2026.01.15
2026.01.15
4 3 2 S17W69 0110 CSO DSO

was AR S11776

area: 0160

14346 2026.01.15
2026.01.15
      S14W63           was AR S11777

location: S13W52

S11780 2026.01.15   3 1 N10W72 0030   HRX  
14347 2026.01.16
2026.01.16
3 2 1 N09W44 0060 HSX CSO was AR S11781

area: 0130

14350 2026.01.18
2026.01.19
      N18W14         was AR S11786

real location: N21W18

SWPC location was N21E04 on 2026.01.23. Apparently they included a spot from AR S11793 the next day

14351 2026.01.18
2026.01.19
5 23 13 S04W34 0030 CAO DRI

beta-gamma

was AR S11787

area: 0070

14349 2026.01.18
2026.01.19
7 25 16 S14W06 0230 DSO DHO was AR S11789

area: 0430

location: S14W05

14352 2026.01.20
2026.01.20
      S02W46           was AR S11790

loction: S01W30

S11791 2026.01.20       S05W41            
S11793 2026.01.20   4   N18W10        
S11794 2026.01.20       S14W55            
14353 2026.01.21
2026.01.22
13 22 10 N18W29 0110 DAI DRI

was AR S11797

area: 0090

location: S17W29

14355 2026.01.21
2026.01.24
2 24 7 S12E31 0020 CAO DRO was AR S11798

area: 0050

location: S13E32

S11799 2026.01.21       N05W16            
14354 2026.01.22
2026.01.22
1 2 1 S11W27 0010 AXX AXX was AR 11800

area: 0007

location: S11W31

S11801 2026.01.22       N08W29          
S11806 2026.01.23   3 1 N26E53 0006   BXO  
S11807 2026.01.24   3 2 N07W44 0010   BXO  
S11808 2026.01.24       N15W38          
S11809 2026.01.24   3 2 N18E16 0010   CRO  
S11810 2026.01.24   3   N08E12 0004   AXX  
S11812 2026.01.25   2 1 S11E08 0006   HRX    
S11813 2026.01.25   1   N17E48 0001   AXX    
Total spot count: 41 130 60  
Sunspot number: 131 300 200  (total spot count + 10 * number of spotted regions)
Weighted SN: 81 178 108  (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): 144 165 160  

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2024.05 187.7 191.9 172.1 149.1 (+4.6) 23.56
(SC25 peak)
2024.08  246.1
(SC25 peak)
252.2 216.0  (SC25 peak) 156.8 (+1.8) 15.96
2024.10 221.0 219.6 165.8 160.9 (+1.5) (SC25 solar max) 18.99
2024.11 199.6 195.3 154.1 157.2 (-3.7) 9.33
2024.12 197.3 191.2 154.6 151.2 (-6.0) 8.42
2025.01 190.3 184.2 137.0 146.2 (-5.0) 13.17
2025.02  184.2 179.7 155.7 139.8 (-6.4) 14.42
2025.03 163.7 162.1 134.2 135.9 (-3.9) 15.96
2025.04 162.5 163.6 141.4 133.3 (-2.6) 17.62
2025.05  135.3 138.3 78.5 128.6 (-4.7) 17.26
2025.06 131.3 135.4 114.6 124.7 (-3.9) 21.43
2025.07 137.8 142.3 125.9 (122.4 projected, -2.3) 11.80
2025.08 154.9 158.7 133.7 (119.3 projected, -3.1) 9.97
2025.09 154.4 156.0 129.7 (115.8 projected, -3.5) 14.02
2025.10 139.5 138.6 114.6 (111.8 projected, -4.0) 15.64
2025.11 140.3 137.3 91.7 (109.6 projected, -2.2) 21.01
2025.12 160.8 155.8 124.0 (108.0 projected, -1.6) 13.35
2026.01 152.2 (1)   96.5 (2A) / 119.7 (2B) / 144.4 (2C)
ISN to date: 118. At this level SSN
for July 2025 will become: 122.6
(104.0 projected, -4.0) (25.5)
2026.02       (99.9 projected, -4.1)  
2026.03       (95.5 projected, -4.4)  
2026.04       (91.8 projected, -3.7)  
2026.05       (90.5 projected, -1.3)  
2026.06       (88.4 projected, -2.1)  

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 October 2025

Sunspot activity was on a decreasing trend from September 2024 until mid August 2025 (using the average solar flux over 3 solar rotations as a proxy). Then a strong surge in activity saw solar flux peak in late August 2025 just below the largest peaks seen in 2024. A slow decrease in activity from the August level has been observed in September and October 2025.

All 365 day smoothed sunspot numbers reached a maximum on October 11-12, 2024
. This became the peak of SC25 (365 day smoothed peaks: STAR 1K: 236.1, STAR 2K: 364.3, NOAA SN: 156.0, ISN: 163.9), while 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.