Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 15, 2026 at 17:30 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 (October 11, 2026)
Solar cycle Solar cycles 23-25 (October 1, 2026) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (October 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 (October 1, 2026) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (October 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 under the influence of effects associated with CH1404. Solar wind speed at SOHO ranged between 513 and 674 km/sec, averaging 603 km/sec (+58 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 123.2 - increasing 26.4 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 131.64 (183 days ago). The 81 day average solar flux at 1 AU was 115.2 (41 days ago, this is 29.2% 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: 9.5). Three hour interval K indices: 33233231 (planetary), 43133232 (Boulder), 44212245 (Andenes).

The background x-ray flux is at the class B5 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 150) and in 6 active regions using 1K resolution (SN: 99) SDO/HMI images.

AR 14548 [S12W78] decayed slowly and quietly.
AR 14551 [S13E07] developed slowly with new small and tiny spots forming, especially around the large leader spot. An M flare is possible. C1 flares: C1.1 @ 03:56, C1.3 @ 08:35, C1.0 @ 13:23, C1.3 @ 13:36, C1.3 @ 14:34, C1.9 @ 14:44, C1.0 @ 15:35, C1.0 @ 16:29 UT
AR 14553 [N07E20] was quiet and stable.
AR 14554 [N08E32] decayed slowly and quietly.
AR 14555 [S08W41] developed slowly and quietly.
AR 14556 [N03E46] decayed slowly and could soon become spotless.
AR 14557 [N07E44] mostly quiet and stable.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C6.9 02:21 behind NW limb 14549 GOES18  
C2.2 15:57 S12E13 14551 GOES18  

Coronal mass ejections (CMEs)

October 12-13: No obviously Earth directed CMEs were observed.
October 14: An extensive filament eruption, mainly in the northeast quadrant, was observed before noon. The associated CME could have Earth directed components.

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 (CH1404) was Earth facing on October 10-12. A recurrent positive polarity southern hemisphere coronal hole (CH1405) will likely rotate across the central meridian on October 16-17.

Forecast

The geomagnetic field is expected to be at quiet to unsettled levels on October 15-16 due to effects associated with CH1404. Mostly quiet levels are expected on October 17-18, however, compnonents of the October 14 CME could reach Earth and cause unsettled to minor storm levels.

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
14548 2026.10.02
2026.10.03
1 1 1 S13W79 0020 HSX HRX was AR S12392

location: S12W78

14552 2026.10.08
2026.10.09
      N23W87           was AR S12406

location: N22W85

14551 2026.10.08
2026.10.09
23 47 27 S15E07 0500 EKI EKI beta-gamma

was AR S12407

area: 0780

location: S13E07

S12410 2026.10.09       S08W17            
S12412 2026.10.10       N19W32            
14553 2026.10.10
2026.10.11
1 7 1 N07E20 0010 AXX CRO was AR S12413

area: 0020

14555 2026.10.11 5 8 3 S06W43 0010 BXO CRI was AR S12414

area: 0040

location: S08W41

14554 2026.10.11
2026.10.12
1 4   N07E33 0010 AXX AXX was AR S12415

location: N08E32

14556 2026.10.12
2026.10.13
4 1 1 N03E45 0010 BXO AXX was AR S12416, see AR 14557 as well

area: 0002

location: N03E46

S12417 2026.10.12       S23W22            
14557 2026.10.13 8 12 6 N07E44 0030 CRO CRI split off from AR S12416
14558 2026.10.13
2026.10.14
1     S08W34 0010 AXX     was AR S12418

"spotless"

Total spot count: 44 80 39  
Sunspot number: 124 150 99  (total spot count + 10 * number of spotted regions)
Weighted SN: 62 102 61  (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): 124 75 74 (Effective 2026.09.19: SWPC adjustment changed from 1.1 to 1.0, STAR 2K adjustment changed from 0.55 to 0.5, STAR 1K adjustment changed from 0.8 to 0.75)

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
2025.07 137.8 142.3 125.9 122.5 (-2.2) 11.80
2025.08 154.9 158.7 133.7 118.4 (-4.1) 9.97
2025.09 154.4 156.0 129.7 113.1 (-5.3) 14.02
2025.10 139.5 138.6 114.6 108.5 (-4.6) 15.64
2025.11 140.3 137.3 91.7 106.9 (-1.6) 21.01
2025.12 160.8 155.8 124.0 107.0 (-0.1) 13.35
2026.01 148.7 144.0 115.0 104.2 (-2.8) 22.47
2026.02 136.4 133.1 77.4 99.8 (-4.4) 12.88
2026.03 131.0 129.7 86.6 94.5 (-5.3) 15.44
2026.04  120.0 120.9 79.3 (89.6 projected, -4.9) 12.10
2026.05 125.4 128.2 101.4 (87.2 projected, -2.4) 9.80
2026.06 137.9 142.2 94.3 (84.1 projected, -3.1) 9.57
2026.07 134.7 139.0 78.1 (79.2 projected, -4.9) 10.16
2026.08 116.1 119.0 76.0 (77.0 projected, -2.2) 8.67
2026.09 105.0 106.1 60.3 (76.1 projected, -0.9) 7.54
2026.10 110.1 (1)   34.5 (2A) / 76.4 (2B) / 68.9 (2C) (74.0 projected, -2.1) (13.9)
2026.11       (71.2 projected, -2.8)  
2026.12       (68.0 projected, -3.2)  
2027.01       (65.6 projected, -2.4)  
2027.02       (63.8 projected, -1.8)  
2027.03       (62.5 projected, -1.3)  

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 March 2026

Solar activity appears to have exited the solar max phase as of February 2026 with a strong decrease in the number of sunspots observed. The northern polar field has weakened considerably over the last months, and although there is a chance the the field could recover over the next 1-2 years, there is an increasing chance that solar cycle 26 will be very weak. The southern polar field is not impressive either, however, a southern polar coronal hole has formed early in 2026 and appears to be growing.

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.