Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 9, 2026 at 06:25 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 active levels on January 8. Solar wind speed at SOHO ranged between 344 and 449 km/sec, averaging 376 km/sec (+17 km/sec compared to the previous day). The above 10 MeV proton flux was at background levels all day.

Solar flux density measured at 22h UT on 2.8 GHz was 131.7 - decreasing 2.8 over the previous solar rotation. The measurements at 18 and 20h UT were both flare enhanced, thus using the 22h measurement.

The 365 day average solar flux at 1 AU was 153.42 (183 days ago). The 81 day average solar flux at 1 AU was 143.6 (41 days ago, this is 47.1% 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 13 (STAR Ap - based on the average of three hour interval ap indices: 13.4). Three hour interval K indices: 43421123 (planetary), 33322222 (Boulder), 65332135 (Andenes).

The background x-ray flux is at the class B7 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 8 active regions using 2K resolution (SN: 165) and in 6 active regions using 1K resolution (SN: 100) SDO/HMI images.

AR 14334 [S15W05] decayed slowly and produced 2 CMEs.
AR 14336 [S09E27] gained spots, however, the magnetic delta configuration decreased in area and the region produced only low level C flares. C1 flares: C1.3 @ 08:33, C1.1 @ 12:50, C1.2 @ 14:11, C1.0 @ 15:07, C1.1 @ 22:21 UT
AR 14337 [N25W50] decayed slowly and was mostly quiet. C1 flares: C1.7 @ 03:07, C1.1 @ 03:54, C1.1 @ 04:01, C1.5 @ 04:46, C1.0 @ 06:13 UT
New AR 14338 [S04E35] emerged on January 6 and was noticed by SWPC 2 days later as the region began to decay.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S11745 [S26W15] was quiet and stable.
AR S11753 [S14W40] decayed slowly and quietly.
New AR S11756 [S14E18] emerged with tiny spots.
New AR S11757 [S06W04] was observed with a tiny spot in an old plage area.

AR 14324 at the northwest limb produced a C1.2 flare at 01:39 UT.
AR 14325 at the southwest limb was the source of a C1.1 flare at 04:17 UT

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.3 02:27   14325 GOES18  
C4.4 05:42 S19E03 14334 GOES18 CME
C2.7 16:09   14336 GOES18  
C5.6 17:29   14334 GOES18 LDE, CME, weak type IV radio sweep
C3.4 19:56   14334 GOES18 weak type II radio sweep

Coronal mass ejections (CMEs)

January 6: A partial halo CME was observed after a C2 flare in AR 14334 at 00:21 UT. The CME could reach Earth on January 9.
January 7: No obviously Earth directed CMEs were observed in available coronagraph imagery.
January 8: A partial halo CME was observed after a C4.4 flare in AR 14334 at 05:42 UT. There is a chance the CME could reach Earth on January 11. A partial halo (possibly a very faint halo) CME was observed after the C5 long duration event in AR 14334 peaking at 17:29 UT. This CME could overtake the previous CME and reach Earth on January 11. A full halo CME from a backsided source was observed beginning just before noon.

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 (CH1338) will be Earth facing on January 6-12, although likely too far to the north on January 9-10 to cause a disturbance. A recurrent trans equatorial negative polarity coronal hole (CH1338) will likely rotate across the central meridian on January 10.

Forecast

The geomagnetic field is expected to be at quiet to minor storm levels on January 9-11 due to combined effects from CH1338 and several CMEs. Quiet to unsettled levels are likely on January 12 while effects from CH1339 and the easternmost parts of CH1338 could cause quiet to active levels on January 13-14.

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
14324 2025.12.26
2025.12.26
1     N25W93 0120 HSX    

was AR S11721

rotated out of view

14330 2025.12.27
2025.12.29
      S16W84           was AR S11724

location: S18W76

14331 2025.12.28
2025.12.29
      S25W74           was AR S11729
14332 2025.12.30
2025.12.31
      N14W81           was AR S11732

location: N13W72

14335 2025.12.31
2026.01.03
      S22W67         was AR S11735

location: S22W60

14333 2026.01.01
2026.01.02
2     S11W80 0010 BXO    

was AR S11738+S11739

14334 2026.01.01
2026.01.02
10 19 7 S16W06 0150 DAO DAO

was AR S11740

location: S15W05

S11743 2026.01.02       N10W26            
S11745 2026.01.03   5 2 S25W15 0008   AXX  
14336 2026.01.04
2026.01.04
12 41 23 S10E28 0420 EKI EKC beta-gamma-delta

was AR S11747

area: 0770

location: S09E27

14337 2026.01.04
2026.01.05
7 6 2 N25W49 0020 DAO CRO

was AR S11748

location: N25W50

SWPC classification misrepresents the current spots

S11749 2026.01.04       N00W39            
S11753 2026.01.06   1   S14W40 0001   AXX  
14338 2026.01.06
2026.01.08
3 3 2 S05E34 0010 BXO CRO was AR S11754

location: S04E35

S11755 2026.01.07       N14E04          
S11756 2026.01.08   9 4 S14E18 0025   BXO    
S11757 2026.01.08   1   S06W04 0003   AXX    
Total spot count: 35 85 40  
Sunspot number: 95 165 100  (total spot count + 10 * number of spotted regions)
Weighted SN: 60 106 71  (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): 105 91 80  

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 78.5 128.5 (-4.8) 17.26
2025.06 131.3 135.4 114.6 124.7 (-3.8) 21.43
2025.07 137.8 142.3 125.6 (122.4 projected, -2.3) 11.80
2025.08 154.9 158.7 133.5 (119.3 projected, -3.1) 9.97
2025.09 154.4 156.0 129.8 (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 (109.5 projected, -2.3) 21.01
2025.12 160.8 155.8 124.0 (108.0 projected, -1.5) 13.35
2026.01 152.9 (1)   28.4 (2A) / 110.0 (2B) / 122.5 (2C) (104.0 projected, -4.0) (10.7)
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.