Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 31, 2026 at 05:55 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 30 under the weakening influence of effects associated with CH1341. Solar wind speed at SOHO ranged between 460 and 628 km/sec, averaging 549 km/sec (-123 km/sec compared to the previous day). The high latitude magnetometer at Andenes was at quiet to minor 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 127.5 - decreasing 37.7 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 150.96 (183 days ago). The 81 day average solar flux at 1 AU was 145.5 (41 days ago, this is 48.3% 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 10 (STAR Ap - based on the average of three hour interval ap indices: 9.8). Three hour interval K indices: 43221102 (planetary), 43221322 (Boulder), 44332115 (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 12 active regions using 2K resolution (SN: 233) and in 10 active regions using 1K resolution (SN: 147) SDO/HMI images.

AR 14349 [S14W71] decayed slowly and was mostly quiet. C1 flares: C1.1 @ 15:15, C1.1 @ 15:37, C1.1 @ 16:31, C1.2 @ 19:51 UT
AR 14355 [S15W27] was quiet and stable.
AR 14357 [S12W48] decayed slowly and was mostly quiet. C1 flares: C1.4 @ 18:41 UT
AR 14358 [N14E23] gained tiny spots and was quiet.
AR 14359 [N21E05] developed slowly and quietly.
AR 14360 [S14E26] was quiet and stable.
AR 14362 [S17E59] was mostly quiet and stable. C1 flares: C1.4 @ 03:59, C1.7 @ 13:32 UT
AR 14363 [S24E59] decayed slowly and was mostly quiet. C1 flares: C1.7 @ 08:52 UT
New AR 14365 [N26W11] rotated into view on January 23 and was numbered by SWPC 7 days later.C1 flares: C1.6 @ 07:11 UT
New AR 14366 [N14E63] rotated into view on January 29 and developed many tiny and small spots the next day. C1 flares: C1.6 @ 05:35, C1.1 @ 06:36, C1.3 @ 07:51, C1.9 @ 10:35, C1.6 @ 13:26, C1.1 @ 20:59, C1.3 @ 23:44 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S11814 [N12W06] was quiet and stable.
AR S11826 [S20E10] was quiet and stable.

AR 14351 behind the southwest limb produced C1 flares: C1.3 @ 00:29, C1.5 @ 05:20, C1.0 @ 22:13 UT
A C1.0 flare was recorded at 14:18 UT from a source behind the northeast limb.
C1 flares from unidentified source due to missing imagery: C1.6 @ 00:56 UT

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment

Coronal mass ejections (CMEs)

January 28-30: 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 at quiet to active levels on January 30 due to effects associated with CH1341. Quiet to unsettled conditions are likely on January 31 and February 1.

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
14350 2026.01.18
2026.01.19
      N18W84           was AR S11786

location: N22W86

14349 2026.01.18
2026.01.19
4 7 5 S14W73 0130 CSO CAO was AR S11789

area: 0090

location: S14W71

14355 2026.01.21
2026.01.24
  25 6 S13W35 0040   BXO was AR S11798

location: S15W27

14365 2026.01.23
2026.01.30
1 4 2 N28W12 0010 AXX BXO was AR S11806

location: N26W11

14361 2026.01.24
2026.01.28
      N19W56         was AR S11809

location: N18W52

14356 2026.01.25
2026.01.26
      S10W62           was AR S11810

location: S11W53

S11813 2026.01.25       N17W17            
S11814 2026.01.26   1   N12W06 0002   AXX  
14357 2026.01.26
2026.01.27
5 13 5 S13W47 0020 CAO CRI was AR S11816

area: 0030

location: S12W48

14358 2026.01.26
2026.01.27
2 13 6 N14E23 0010 AXX BXO was AR S11817

area: 0030

S11818 2026.01.26       S32W39            
14360 2026.01.27
2026.01.28
1 7 2 S15E26 0010 AXX CRO was AR S11819

area: 0020

location: S14E26

14359 2026.01.27
2026.01.28
1 11 3 N18E01 0010 AXX CRO was AR S11820

area: 0020

location: N21E05

S11821 2026.01.27       S04W42          
14362 2026.01.28 1 2 1 S17E58 0020 HSX CSO was AR S11822

area: 0120

SWPC area is way off

14363 2026.01.28
2026.01.29
3 7 4 S24E59 0030 CAO CRO was AR S11823
14366 2026.01.29
2026.01.30
4 19 13 N16E65 0060 DAI DRI beta-gamma

was AR S11825

location: N14E63

S11826 2026.01.29   4   S20E10 0005   BXO  
Total spot count: 22 113 47  
Sunspot number: 112 233 147  (total spot count + 10 * number of spotted regions)
Weighted SN: 47 138 72  (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): 123 128 118  

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
2026.01 149.7 (1)   111.6 (2A) / 119.0 (2B) / 140.6 (2C)
ISN to date: 117. At this level SSN
for July 2025 will become: 122.7
(104.0 projected, -4.0) (23.8)
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.