Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 15, 2026 at 07:40 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 unsettled to major storm levels on March 14 under the influence of effects associated with CH1349. Solar wind speed at SOHO ranged between 619 and 739 km/sec, averaging 683 km/sec (+143 km/sec compared to the previous day). The high latitude magnetometer at Andenes was at unsettled to severe 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 111.6 - decreasing 6.3 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 146.31 (183 days ago). The 81 day average solar flux at 1 AU was 140.4 (41 days ago, this is 45.1% 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 40 (STAR Ap - based on the average of three hour interval ap indices: 40.3). Three hour interval K indices: 66545434 (planetary), 54444333 (Boulder), 67534456 (Andenes).

The background x-ray flux is at the class B4 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 8 active regions using 2K resolution (SN: 135) and in 6 active regions using 1K resolution (SN: 88) SDO/HMI images.

AR 14391 [N07W07] decayed slowly and quietly.
AR 14392 [S15E41] gained tiny spots and was mostly quiet. C1 flares: C1.1 @ 17:00 UT
AR 14393 [N13E12] decayed slowly and was mostly quiet. C1 flares: C1.1 @ 06:11, C1.5 @ 19:45 UT
New AR 14394 [S12E44] rotated into view on March 12 and was numbered by SWPC 2 days later. The spot group appears to be decaying slowly.
New AR 14395 [S04E54] began to emerge before noon and produced the largest flare of the day just before the end of the UT day.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S11925 [S13E05] was quiet and stable.
New AR S11930 [N24W02] emerged with a tiny spot.
New AR S11931 [S01W01] emerged with a tiny spot.

AR 14384 produced C1 flares while rotating over the northwest limb: C1.2 @ 01:28, C1.2 @ 01:37, C1.3 @ 01:53, C1.0 @ 05:08, C1.0 @ 05:28, C1.0 @ 05:37, C1.1 @ 06:19, C1.1 @ 06:28, C1.0 @ 06:53, C1.1 @ 07:03, C1.1 @ 08:10, C1.3 @ 09:44, C1.4 @ 10:04, C1.0 @ 11:50, C1.3 @ 15:36, C1.1 @ 16:02, C1.2 @ 16:33, C1.0 @ 21:29, C1.7 @ 21:34, C1.1 @ 23:08 UT

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.1 12:53   14384 GOES18  
C2.4 23:48   14395 GOES18  

Coronal mass ejections (CMEs)

March 12-14: 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 positive polarity coronal hole (CH1349) will rotate across the central meridian on March 11-17.

Forecast

The geomagnetic field is expected to be at quiet to minor storm levels on March 15 and quiet to unsettled levels on March 16-18 due to effects assocciated with CH1349.

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
14384 2026.03.01
2026.03.01
11     N10W94 0230 DAI     was AR S11899

rotated out of view

SWPC spot count, area and classification is unchanged from the previous day

14388 2026.03.05
2026.03.09
      S14W85         was AR S11910

location: S13W85

S11911 2026.03.05       S23W50            
14387 2026.03.07
2026.03.08
      N08W19         was AR S11914

location: N08W16

14389 2026.03.09
2026.03.10
      N10W02         was AR S11915

location: N14W01

14390 2026.03.09       N26W26         was AR S11918

location: N27W24

14393 2026.03.09
2026.03.11
4 15 9 N13E10 0030 CRO CRI was AR S11919/AR 14389

area: 0040

location: N13E12

S11920 2026.03.09       S08W51            
14391 2026.03.10
2026.03.11
3 9 4 N06W06 0010 BXO CRO was AR S11921

area: 0030

location: N07W07

14392 2026.03.11
2026.03.11
3 12 7 S15E41 0090 CSO CSI beta-gamma

was AR S11922

area: 0250

S11924 2026.03.11       N06W52            
S11925 2026.03.12   4   S13E05 0008   AXX  
14394 2026.03.12
2026.03.14
1 2 1 S12E44 0010 AXX HRX was AR S11926
S11928 2026.03.13       N07E28          
14395 2026.03.14
2026.03.14
3 11 6 S04E53 0010 BXO DRI   was AR S11929

area: 0060

location: S04E54

S11930 2026.03.14   1 1 N24W02 0002   AXX    
S11931 2026.03.14   1   S01W01 0001   AXX    
Total spot count: 25 55 28  
Sunspot number: 85 135 88  (total spot count + 10 * number of spotted regions)
Weighted SN: 38 72 45  (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): 94 74 70  

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) 12.88
2026.03 133.5 (1)   37.7 (2A) / 83.5 (2B) / 87.6 (2C) (94.3 projected, -4.6) (13.1)
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.

--------------------------------------------------------------------------------------

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.