Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 24, 2026 at 06:45 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 (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 unsettled to active levels on January 23 under the influence of effects from CH1340. Solar wind speed at SOHO ranged between 469 and 618 km/sec, averaging 535 km/sec (-35 km/sec compared to the previous day). The high latitude magnetometer at Andenes was at unsettled to severe storm levels. The above 10 MeV proton flux decreased gradually and was near 2 pfu at the end of the UT day.

Solar flux density measured at 20h UT on 2.8 GHz was 179.5 - increasing 1.8 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 151.61 (183 days ago). The 81 day average solar flux at 1 AU was 147.4 (41 days ago, this is 49.5% 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 26 (STAR Ap - based on the average of three hour interval ap indices: 26.5). Three hour interval K indices: 44443444 (planetary), 34333533 (Boulder), 54443764 (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 16 active regions using 2K resolution (SN: 364) and in 14 active regions using 1K resolution (SN: 252) SDO/HMI images.

AR 14341 [S10W46] decayed slowly and was mostly quiet. C1 flares: C1.8 @ 09:36 UT
AR 14342 [N17W43] was mostly quiet and stable. Note that SWPC groups AR S11780 with this AR. C1 flares: C1.8 @ 19:56 UT
AR 14345 [S17W42] decayed slowly and was mostly quiet.
AR 14347 [N10W18] was quiet and stable.
AR 14348 [S17W74] decayed slowly and quietly.
AR 14349 [S13E21] developed slowly and was mostly quiet.
AR 14350 [N21E07] decayed and was spotless at noon, then tiny spots reemerged.
AR 14351 [S04W07] developed early in the day, then decayed slowly and quietly. C1 flares: C1.9 @ 00:10 UT
AR 14353 [N18W02] displayed slow decay after noon. C1 flares: C1.6 @ 01:07, C1.7 @ 11:34 UT
AR 14354 [S11W00] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S11780 [N11W46] decayed further and was quiet.
AR S11793 [N18E14] developed slowly and was mostly quiet.
AR S11798 [S12E56] has tiny spots spread over a large area consisting of mostly plage. C1 flares: C1.6 @ 04:16 UT
AR S11801 [N08W04] developed slowly and quietly.
AR S11802 [S25W34] was quiet and stable.
New AR S11806 [N26E79] rotated into view with a tiny spot.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.2 00:24   14345 GOES18  
C3.2 01:19   14353 GOES18  
C3.2 01:25   14345 GOES18  
C3.4 01:40   14351 GOES18  
C3.7 01:57   14351 GOES18 simultaneous flares in ARs 14353 and 14354
C3.7 02:09   14353 GOES18  
C3.4 02:22   14351 GOES18  
C2.6 02:41   14351 GOES18 simultaneous flares in ARs S11798 and 14349
C2.6 05:46   14341 GOES18  
C2.6 06:06   14349 GOES18  
C2.4 06:15   14351 GOES18  
C2.8 06:26   14351 GOES18  
C2.5 10:15   14345 GOES18  
C3.3 13:14   S11798 GOES18  
C2.1 14:02   14345 GOES18  
C2.0 15:05   S11793 GOES18  
C5.9 23:29   near S11798 GOES18 LDE, filament eruption

Coronal mass ejections (CMEs)

January 22-24: 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 huge recurrent trans equatorial positive polarity coronal hole (CH1340) was Earth facing on January 15-22. A recurrent trans equatorial negative polarity coronal hole (CH1341) will likely rotate across the central meridian on January 24-25.

Forecast

The geomagnetic field is expected to be at quiet to active levels on January 24-25 due to effects associated with CH1340 and 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
10 18 12 S11W49 0200 CAO CAO

was AR S11770

area: 0290

location: S10W46

14342 2026.01.14
2026.01.14
15 4 1 N13W45 0180 DSO CSO

was AR S11772

area: 0200

location: N17W43

SWPC includes the spots of AR S11780

14344 2026.01.15       N19W56        

location: N18W53

14345 2026.01.15
2026.01.15
20 28 19 S17W42 0130 ESO ESI beta-gamma

was AR S11776

area: 0230

14346 2026.01.15
2026.01.15
      S14W35           was AR S11777

location: S13W26

S11780 2026.01.15   15 10 N11W46 0070   CAO  
14347 2026.01.16
2026.01.16
1 8 3 N10W19 0060 HSX DSO was AR S11781

area: 0160

S11783 2026.01.16       N02W36            
14348 2026.01.18
2026.01.18
4 3 2 S17W71 0020 HSX AXX was AR S11784

area: 0010

location: S17W74

strange classification by SWPC

14350 2026.01.18
2026.01.19
  10 2 N21E04 0020   BXO was AR S11786

location: N21E07

14351 2026.01.18
2026.01.19
20 27 17 S05W08 0080 DAI DAI

was AR S11787

area: 0120

S11788 2026.01.18       N04W34            
14349 2026.01.18
2026.01.19
4 22 10 S15E21 0120 HSX DHO was AR S11789

area: 0460

location: S13E21

14352 2026.01.20
2026.01.20
      S02W19           was AR S11790

loction: S01W17

S11791 2026.01.20       S05W15            
S11793 2026.01.20   8 2 N18E14 0020   CRO  
S11794 2026.01.20       S14W29            
14353 2026.01.21
2026.01.22
25 34 23 N17W03 0100 DAO DAI beta-gamma

was AR S11797

area: 0230

location: S18W02

S11798 2026.01.21   12 5 S12E56 0030   BXO  
S11799 2026.01.21       N05E10            
14354 2026.01.22
2026.01.22
6 6 2 S12W00 0010 CAO? BXO was AR 11800

area: 0040

location S11W00

SWPC classification is obviously incorrect

S11801 2026.01.22   6 4 N08W04 0020   DRO  
S11802 2026.01.22   2   S24W34 0002   BXO  
S11803 2026.01.22       S22W56          
S11806 2026.01.23   1   N26E79 0001   AXX    
Total spot count: 105 204 112  
Sunspot number: 195 364 252  (total spot count + 10 * number of spotted regions)
Weighted SN: 150 255 163  (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): 215 200 202  

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
2026.01 150.7 (1)   87.5 (2A) / 118.0 (2B) / 142.2 (2C)
ISN to date: 114. At this level SSN
for July 2025 will become: 122.5
(104.0 projected, -4.0) (26.4)
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.