Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 8, 2026 at 15:50 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 levels on January 7. Solar wind speed at SOHO ranged between 309 and 414 km/sec, averaging 359 km/sec (+3 km/sec compared to the previous day). The above 10 MeV proton flux was at background levels all day.

Solar flux density measured at 20h UT on 2.8 GHz was 135.0 - decreasing 11.9 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 153.49 (183 days ago). The 81 day average solar flux at 1 AU was 143.9 (41 days ago, this is 47.3% 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 4 (STAR Ap - based on the average of three hour interval ap indices: 3.5). Three hour interval K indices: 00001122 (planetary), 11002132 (Boulder), 00000233 (Andenes).

The background x-ray flux is at the class B8 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 12 active regions using 2K resolution (SN: 219) and in 11 active regions using 1K resolution (SN: 164) SDO/HMI images.

AR 14323 [S17W82] decayed slowly and was mostly quiet. C1 flares C1.2 @ 02:25 UT
AR 14324 [N24W80] was mostly quiet and stable. C1.1 @ 08:40 UT
AR 14325 [S10W83] decayed further and was mostly quiet. C1 flares: C1.3 @ 12:13, C1.4 @ 14:05, C1.7 @ 16:20, C1.1 @ 19:52 UT
AR 14333 [S10W64] was mostly quiet and stable. C1 flares: C1.3 @ 23:24 UT
AR 14334 [S15E08] decayed slowly and produced several C flares. C1 flares: C1.3 @ 08:56, C1.5 @ 14:01, C1.9 @ 14:19, C1.2 @ 17:42 UT
AR 14335 [S22W47] reemerged with a tiny spot.
AR 14336 [S09E40] was mostly quiet despite the magnetic delta configuration in the leading penumbra. C1 flares: C1.1 @ 01:39, C1.1 @ 14:19, C1.0 @ 15:17, C1.2 @ 18:51, C1.1 @ 21:09, C1.1 @ 21:18, C1.6 @ 21:58 UT
New AR 14337 [N26W35] emerged on January 4 and was numbered by SWPC 3 days later. The region was the source of a few low level C flares. C1 flares: C1.2 @ 03:11, C1.0 @ 03:29, C1.2 @ 08:51, C1.0 @ 09:49, C1.3 @ 00:04 (flare began at: 23:58) UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S11745 [S25W02] reemerged with tiny spots.
AR S11753 [S14W24] was quiet and stable.
AR S11754 [S04E48] developed slowly and quietly.
New AR S11755 [N14E17] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.5 00:11   14334 GOES18  
C2.9 03:54 S16E16 14334 GOES18  
C2.6 04:09   14337 GOES18  
C2.8 05:28   14337 GOES18  
C7.4 06:12   14334 GOES18  
C2.1 11:32   14334 GOES18  
C2.1 22:07   14336 GOES18  
C3.2 23:14   14337 GOES18  

Coronal mass ejections (CMEs)

January 5, 7: No obviously Earth directed CMEs were observed in available coronagraph imagery.
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 8: A CME was observed after a C4.4 flare in AR 14334 at 05:42 UT. The CME could reach Earth on January 11.

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 6-10. 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 levels on January 7-8. Effects related to CH1338 and a CME could cause quiet to minor storm levels on January 9-11.

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
14323 2025.12.25
2025.12.26
6 4 2 S17W83 0110 DSO CSO

was AR S11719

area: 0120

14325 2025.12.26
2025.12.27
6 4 3 S09W90 0120 FAO HRX

was AR S11720

area: 0030

location: S10W83

14324 2025.12.26
2025.12.26
1 1 1 N25W79 0060 HSX HSX

was AR S11721

area: 0100

location: N24W80

14330 2025.12.27
2025.12.29
      S16W70           was AR S11724

location: S18W63

14331 2025.12.28
2025.12.29
      S25W60           was AR S11729
14329 2025.12.29
2025.12.29
      S12W76           was AR S11731

location: S13W67

14332 2025.12.30
2025.12.31
      N14W67           was AR S11732

location: N13W59

14335 2025.12.31
2026.01.03
  1   S22W53 0002   AXX   was AR S11735

location: S22W47

14333 2026.01.01
2026.01.02
6 7 5 S10W66 0010 BXO DRO

was AR S11738+S11739

area: 0020

location: S10W64

14334 2026.01.01
2026.01.02
12 23 14 S16E07 0150 CAI DAO beta-gamma

was AR S11740

area: 0200

location: S15E08

S11743 2026.01.02       N10W13            
S11745 2026.01.03   2 1 S25W02 0005   AXX    
14336 2026.01.04
2026.01.04
12 27 16 S10E41 0300 EKI EKC beta-delta

was AR S11747

area: 0810

location: S09E40

14337 2026.01.04
2026.01.05
5 15 6 N25W35 0020 CRO DRI beta-gamma

was AR S11748

area: 0040

location: N26W35

S11749 2026.01.04       N00W26            
S11752 2026.01.05       N12W57            
S11753 2026.01.06   6 2 S14W24 0010   BXO  
S11754 2026.01.06   6 3 S04E48 0020   CRO  
S11755 2026.01.07   3 1 N14E17 0005   AXX    
Total spot count: 48 99 54  
Sunspot number: 118 219 164  (total spot count + 10 * number of spotted regions)
Weighted SN: 81 136 91  (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): 130 120 131  

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) 13.8
2026.01 155.9 (1)   25.3 (2A) / 112.1 (2B) / 126.6 (2C) (104.0 projected, -4.0) (10.3)
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.