Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 6, 2026 at 07:45 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 (May 1, 2026)
Solar cycle Solar cycles 23-25 (May 1, 2026) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (May 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 (May 1, 2026) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (May 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 active to minor storm levels early on May 5 under the influence of CME effects, then at quiet levels for the remainder of the day. Solar wind speed at SOHO ranged between 384 and 466 km/sec, averaging 416 km/sec (-11 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 127.5 - increasing 19.1 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 140.77 (183 days ago). The 81 day average solar flux at 1 AU was 125.1 (41 days ago, this is 35.4% 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: 10.4). Three hour interval K indices: 54211011 (planetary), 33322221 (Boulder), 65321111 (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 12 active regions using 2K resolution (SN: 211) and in 11 active regions using 1K resolution (SN: 156) SDO/HMI images.

AR 14425 [N05W74] was mostly quiet and stable. C1 flares: C1.1 @ 08:27, C1.2 @ 13:04, C1.4 @ 13:25, C1.8 @ 14:12, C1.2 @ 14:29, C1.2 @ 14:37 UT
AR 14428 [S22W81] decayed slowly and quietly.
AR 14429 [S04W33] decayed quickly and quietly.
AR 14431 [S16W06] decayed slowly and was mostly quiet. C1 flares: C1.9 @ 08:38, C1.2 @ 14:45, C1.2 @ 15:08 UT
AR 14432 [N12E14] decayed significantly and was mostly quiet. C1 flares: C1.1 @ 02:05, C1.3 @ 05:12 UT
AR 14433 [S16E40] was mostly quiet and stable. C1 flares: C1.2 @ 04:23 UT
AR 14434 [N12E37] decayed slowly and quietly.
AR 14435 [N23E50] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
New AR S12043 [N10W75] emerged with tiny spots before noon, then decayed slowly.
New AR S12044 [S08E20] emerged with tiny spots.
New AR S12045 [S18W45] emerged with a tiny spot.
New AR S12046 [N17W32] emerged with a tiny spot.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C6.0 05:27 behind NW limb 14424 GOES18  

Coronal mass ejections (CMEs)

May 3-5: 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 positive polarity trans equatorial coronal hole (CH1363) will rotate across the central meridian on May 4-7.

Forecast

The geomagnetic field is expected to be at quiet levels on May 6. Quiet to minor storm conditions are possible on May 7-8 due to effects from CH1363.

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
14425 2026.04.24
2026.04.24
4 2 2 N06W75 0180 HSX HKX

was AR S12011

area: 0300

location: N05W74

14427 2026.04.24
2026.04.25
      S29W70           was AR S12013

location: S31W62

14428 2026.04.27
2026.04.28
3 4 2 S23W78 0140 ESO CSO

was AR S12022

area: 0220

location: S22W81

14429 2026.04.29
2026.04.30
13 21 12 S05W33 0050 CAI CRI

was AR S12025

location: S04W33

14431 2026.04.29
2026.05.01
5 19 8 S16W01 0100 ESO CAO was AR S12026

area: 0250

location: S16W06

14430 2026.04.29
2026.05.01
      N17W86           was AR S12027
S12029 2026.04.30       N07W59            
S12030 2026.04.30       N27W46            
14432 2026.05.01
2026.05.01
8 22 9 N13E12 0040 CAI DRI

area: 0060

location: N12E14

S12033 2026.05.01       N46W30            
S12034 2026.05.01       S18W56          
14433 2026.05.02
2026.05.03
4 13 8 S16E43 0120 DSO DAO was AR S12035

area: 0210

location: S16E40

14434 2026.05.02
2026.05.04
1 4 1 N12E36 0010 AXX BXO was AR S12036

location: N12E37

14435 2026.05.03
2026.05.04
1 1 1 N23E51 0040 HSX HAX was AR S12037

area: 0100

location: N23E50

S12038 2026.05.03       N29W33            
S12039 2026.05.04       S10W34          
S12040 2026.05.04       S10E24          
S12041 2026.05.04       N11W53          
S12042 2026.05.04       N26W18          
S12043 2026.05.05   1 1 N10W75 0006   AXX    
S12044 2026.05.05   2 1 S08E20 0006   BXO    
S12045 2026.05.05   1 1 S18W45 0003   AXX    
S12046 2026.05.05   1   N17W32 0001   AXX    
Total spot count: 39 91 46  
Sunspot number: 119 211 156  (total spot count + 10 * number of spotted regions)
Weighted SN: 74 127 82  (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): 131 116 125  

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
2025.02 184.2 179.7 155.7 139.8 (-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
2025.09 154.4 156.0 129.7 112.9 (-5.3) 14.02
2025.10 139.5 138.6 114.6 108.3 (-4.6) 15.64
2025.11 140.3 137.3 91.7 (105.8 projected, -2.5) 21.01
2025.12 160.8 155.8 124.0 (104.3 projected, -1.5) 13.35
2026.01 148.7 144.0 112.6 (100.4 projected, -3.9) 22.47
2026.02 136.4 133.1 78.2 (96.1 projected, -4.3) 12.88
2026.03 131.0 129.7 85.9 (91.5 projected, -4.6) 15.44
2026.04  120.0 120.9 79.3 (87.6 projected, -3.9) 12.0
2026.05  142.5 (1)   22.3 (2A) / 138.2 (2B) / 93.0 (2C) (86.4 projected, -1.2) (11.5)
2026.06       (84.3 projected, -2.1)  
2026.07       (79.9 projected, -4.4)  
2026.08       (77.7 projected, -2.2)  
2026.09       (76.8 projected, -0.9)  
2026.10       (74.8 projected, -2.0)  

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.