Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 7, 2026 at 08:15 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 (March 1, 2026)
Solar cycle Solar cycles 23-25 (March 1, 2026) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (March 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 (March 1, 2026) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (March 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 on March 6. Solar wind speed at SOHO ranged between 352 and 448 km/sec, averaging 380 km/sec (-17 km/sec compared to the previous day). What appeared to be a weak solar wind shock was observed at 04:47 UT at SOHO, there was a sudden increase in both solar wind speed and density as well as in the total field of the IMF. A transition to a weak CIR associated with CH1348 was observed just before 20h UT at SOHO, and the high speed stream was observed beginning before midnight. 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 142.8 - decreasing 24.6 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 147.03 (183 days ago). The 81 day average solar flux at 1 AU was 140.1 (41 days ago, this is 44.9% 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 7 (STAR Ap - based on the average of three hour interval ap indices: 7.0). Three hour interval K indices: 12212113 (planetary), 03222213 (Boulder), 33303335 (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 10 active regions using 2K resolution (SN: 204) and in 8 active regions using 1K resolution (SN: 131) SDO/HMI images.

AR 14378 [N16W44] was mostly quiet and stable. C1 flares: C1.2 @ 07:28 UT
AR 14380 [S21W28] decayed slowly and quietly.
AR 14381 [N08W13] decayed slowly and was mostly quiet.
AR 14383 [N17W76] developed slowly and was mostly quiet.
AR 14384 [N09E09] was quiet and stable.
AR 14385 [S09E02] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S11903 [S17W09] was quiet and stable.
AR S11910 [S13E22] was quiet and stable.
AR S11911 [S20E53] developed slowly and quietly.
New AR S11913 [S39E43] emerged with a tiny spot.

A C1.2 flare was recorded at 13:42 UT (not attributed to any AR due to missing imagery).

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment

Coronal mass ejections (CMEs)

March 4-5: No obviously Earth directed CMEs were observed in available coronagraph imagery.
March 6: A filament eruption in the southeat quadrant early in the day may have been associated with a faint CME that could reach Earth on March 9.

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 (CH1348) was in an Earth facing position on March 4.

Forecast

The geomagnetic field is expected to be at quiet to active levels on March 7-8 due to effects from CH1348. Quiet to unsettled levels are likely on March 9-10.

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
14379 2026.02.24
2026.02.25
      S19W43         was AR S11882
14378 2026.02.25
2026.02.25
5 14 7 N16W44 0240 CSO DHO beta-gamma

was AR S11886

area: 0460

14383 2026.02.25
2026.03.01
  5 3 N17W78 0080   DAO was AR S11888

location: N17W76

14380 2026.02.25
2026.02.26
  9 3 S21W31 0015   BXO

was AR S11889

location: S21W28

14381 2026.02.27
2026.02.27
10 37 22 N08W11 0200 EAI ESI beta-gamma

was AR S11892

area: 0300

location: N08W13

14385 2026.02.28
2026.03.04
3 8 4 S09E02 0010 CRO CRO was AR S11898

area: 0020

14384 2026.03.01
2026.03.01
5 17 9 N10E14 0260 DHO EKO was AR S11899

area: 0410

location: N09E09

S11902 2026.03.01       S09W51            
S11903 2026.03.02   5 2 S17W09 0010   BXO  
S11904 2026.03.02       S30W48            
S11908 2026.03.04       S22E12            
14386 2026.03.05 2     N15W76 0060 CAO       SWPC error, this is AR 14383. AR 14386 should be deleted
S11909 2026.03.05       S19W15          
S11910 2026.03.05   4   S13E22 0010   BXO  
S11911 2026.03.05   4 1 S20E53 0010   BXO  
S11913 2026.03.06   1   S39E43 0001   AXX    
Total spot count: 25 104 51  
Sunspot number: 75 204 131  (total spot count + 10 * number of spotted regions)
Weighted SN: 53 137 84  (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): 83 112 105  

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
2024.12 197.3 191.2 154.6 151.2 (-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 (-2.3) 11.80
2025.08 154.9 158.7 133.7 118.2 (-4.2) 9.97
2025.09 154.4 156.0 129.7 (113.5 projected, -4.7) 14.02
2025.10 139.5 138.6 114.6 (110.0 projected, -3.5) 15.64
2025.11 140.3 137.3 91.7 (108.3 projected, -1.7) 21.01
2025.12 160.8 155.8 124.0 (107.1 projected, -1.2) 13.35
2026.01 148.7 144.0 112.6 (103.2 projected, -3.9) 22.47
2026.02 136.4 133.1 78.2 (98.9 projected, -4.2) 13.2
2026.03 144.7 (1)   14.5 (2A) / 75.0 (2B) / 95.1 (2C) (94.3 projected, -4.6) (7.6)
2026.04       (90.4 projected, -3.9)  
2026.05       (89.2 projected, -1.2)  
2026.06       (87.1 projected, -2.1)  
2026.07       (82.7 projected, -4.4)  
2026.08       (80.5 projected, -2.2)  

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.