Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 4, 2026 at 07:10 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 minor storm levels on March 3, mainly under the influence of a high speed stream associated with CH1347. Solar wind speed at SOHO ranged between 369 and 451 km/sec, averaging 403 km/sec (+50 km/sec compared to the previous day). The high latitude magnetometer at Andenes was at quiet to major 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 143.5 - decreasing 32.4 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 147.13 (183 days ago). The 81 day average solar flux at 1 AU was 139.1 (41 days ago, this is 44.3 % 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 15 (STAR Ap - based on the average of three hour interval ap indices: 15.3). Three hour interval K indices: 13222335 (planetary), 02333435 (Boulder), 02212356 (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 9 active regions using 2K resolution (SN: 207) and in 8 active regions using 1K resolution (SN: 125) SDO/HMI images.

AR 14378 [N16W04] gained tiny spots and has weak polarity intermixing. C1 flares: C1.1 @ 01:53, C1.0 @ 19:52 UT
AR 14379 [S18W02] was quiet and stable.
AR 14380 [S21E10] decayed slowly and quietly.
AR 14381 [N08E25] gained some tiny and small intermediate spots and was mostly quiet. C1 flares: C1.2 @ 02:10, C1.1 @ 19:13 UT
AR 14383 [N14W41] decayed slowly and quietly.
AR 14384 [N09E50] was much less active than over the previous days. C1 flares: C1.0 @ 03:09, C1.1 @ 12:49, C1.6 @ 14:29, C1.1 @ 19:13, C1.0 @ 20:24 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S11898 [S08E44] developed slowly as new flux emerged.
New AR S11906 [N18W28] emerged with a few spots.
New AR S11907 [N63E00] emerged with a tiny spot at a very high latitude.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.9 00:30   14381 GOES18  
C2.1 00:41   14381 GOES18  
C2.1 16:02 N11E63 14384 GOES18  

Coronal mass ejections (CMEs)

March 1-3: 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 (CH1348) will rotate into an Earth facing position on March 4.

Forecast

The geomagnetic field is expected to be at quiet to unsettled levels on March 4 due to effects associated with CH1347 and quiet on March 5-6.

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
S11880 2026.02.23       N24W41            
14379 2026.02.24
2026.02.25
  20 6 S19W01 0030   BXO was AR S11882

location: S18W02

14378 2026.02.25
2026.02.25
6 32 9 N15W02 0250 CHO DHO beta-gamma

was AR S11886

area: 0430

location: N16W04

S11887 2026.02.25       S12W50            
14383 2026.02.25
2026.03.01
1 3 2 N15W41 0010 AXX BXO was AR S11888

location: N14W41

14380 2026.02.25
2026.02.26
  14 3 S21E11 0020   BXO

was AR S11889

location: S21E10

S11890 2026.02.26       N03W37          
S11891 2026.02.26       S02W48            
14381 2026.02.27
2026.02.27
9 24 14 N08E30 0220 EAO EKI was AR S11892

area: 0350

location: N08E25

14382 2026.02.27
2026.03.01
      N22W76           was AR S11893
S11896 2026.02.28       N24W35            
S11898 2026.02.28   5 2 S08E44 0020   CRO  
14384 2026.03.01
2026.03.01
8 14 7 N10E53 0300 EHO EHO was AR S11899

area: 0460

location: N09E50

S11900 2026.03.01       S09W40            
S11901 2026.03.01       N18W45            
S11902 2026.03.01       S09W12            
S11903 2026.03.02       S18E27          
S11904 2026.03.02       S30W09          
S11905 2026.03.02       S14W47          
S11906 2026.03.03   4 2 N18W28 0030   DRO    
S11907 2026.03.03   1   N63E00 0001   AXX    
Total spot count: 24 117 45  
Sunspot number: 64 207 125  (total spot count + 10 * number of spotted regions)
Weighted SN: 49 153 81  (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): 70 114 100  

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
2026.03 146.0 (1)   7.5 (2A) / 77.0 (2B) / 99.3 (2C) (94.3 projected, -4.6) (9.9)
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.