Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 26, 2026 at 06:45 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 (June 1, 2026)
Solar cycle Solar cycles 23-25 (June 1, 2026) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (June 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 (June 1, 2026) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (June 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 under the influence of effects associated with CH1378. Solar wind speed at SOHO ranged between 611 and 799 km/sec, averaging 696 km/sec (+224 km/sec compared to the previous day). The high latitude magnetometer at Andenes was at unsettled 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 155.9 - increasing 14.2 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 139.74 (183 days ago). The 81 day average solar flux at 1 AU was 126.4 (41 days ago, this is 36.2% 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 23 (STAR Ap - based on the average of three hour interval ap indices: 23.1). Three hour interval K indices: 45424343 (planetary), 46433333 (Boulder), 56335454 (Andenes).

The background x-ray flux is at the class C1 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 10 active regions using 2K resolution (SN: 253) and in 7 active regions using 1K resolution (SN: 138) SDO/HMI images.

AR 14470 [N07W50] decayed and came close to being spotless at noon. Slow development was observed after noon.
AR 14472 [S15W12] decayed slowly and quietly.
AR 14475 [S09E07] displayed some disintegration of the main penumbra. There are still many tiny spots surrounding that penumbra and an M class flare is possible given the level of polarity intermixing. C1 flares: C1.8 @ 05:40, C1.2 @ 11:46 UT
AR 14476 [N08W15] decayed slowly and quietly losing mature penumbra.
AR 14477 [S13E41] decayed early in the day, then developed slowly after noon. C1 flares: C1.4 @ 21:34 UT
AR 14478 [S06E62] is a compact and complex spot group with polarity intermixing and possible a couple of tiny magnetic delta configurations. While the region has major flare potential, it has mostly produced low level C flares over the last days. C1 flares: C1.7 @ 02:01, C1.7 @ 02:17, C1.6 @ 03:48, C1.2 @ 05:07, C1.2 @ 05:28, C1.2 @ 06:45, C1.3 @ 07:31, C1.6 @ 08:03, C1.6 @ 08:24, C1.3 @ 09:32, C1.1 @ 10:18, C1.2 @ 10:35, C1.2 @ 11:22, C1.3 @ 12:03, C1.5 @ 12:15, C1.9 @ 16:11, C1.6 @ 21:07, C1.3 @ 23:22 UT
AR 14479 [N16E44] decayed early in the day and may have been spotless by noon. New flux emerged after noon and several tiny spots formed.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S12167 [S07W04] was mostly quiet and stable. C1 flares: C1.6 @ 07:04 UT
AR S12173 [N15W28] was quiet and stable.
New AR S12174 [N10E03] emerged with a tiny spot.

An active region behind the northwest limb produced a C1.1 flare at 04:40 UT

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.3 00:22   14478 GOES18  
C3.1 00:44   14477 GOES18  
C3.0 01:01   14478 GOES18  
C2.5 01:22   14478 GOES18  
C4.1 02:54   14478 GOES18  
C3.1 03:14   14475 GOES18  
C2.6 03:26   14478 GOES18  
C2.1 05:47   14478 GOES18  
C2.0 08:31   14478 GOES18  
C2.2 09:05   14478 GOES18  
C2.7 13:29 S05E69 14478 GOES18  
C2.1 14:09   14478 GOES18  
C6.6/1N 15:03 S04E58 14478 GOES18  
C2.4 16:27   14477 GOES18  
C2.2 17:15   14478 GOES18  
C2.3 21:14   14478 GOES18  
C2.0 22:02   14475 GOES18  
C4.4 23:46   14478 GOES18  
C5.0 23:48   14478 GOES18 different flare center compared to above flare

Coronal mass ejections (CMEs)

June 23-25: 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 trans equatorial negative polarity coronal hole (CH1378) was Earth facing on June 23-24. A recurrent northern hemisphere negative polarity coronal hole (CH1379) wasEarth facing on June 24-25.

Forecast

The geomagnetic field is expected to be at quiet to active levels on June 26 under the influence of effects associated with CH1378/CH1379 and quiet to unsettled on June 27-28.

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
14471 2026.06.14
2026.06.18
      N17W86           was AR S12144

location: N18W81

14470 2026.06.15
2026.06.16
2 5 4 N08W52 0010 BXO CRO was AR S12149

area: 0015

S12154 2026.06.17       N11W48            
14472 2026.06.18
2026.06.19
  7   S15W12 0010   AXX was AR S12157
S12158 2026.06.18       S14W46            
14473 2026.06.19
2026.06.20
2     S07W04 0010 BXO    

was AR S12160

location: S08E01

SWPC moved this AR to the location of AR S12167 on 2026.06.25

14475 2026.06.20
2026.06.22
16 51 18 S09E07 0250 EKI DKI was AR S12162

area: 0370

S12164 2026.06.21       N37W45            
14476 2026.06.22
2026.06.23
6 16 7 N08W16 0030 DRO DRO

was AR S12165

area: 0060

S12166 2026.06.22       S24W26            
S12167 2026.06.22   8 4 S07W04 0020   CRO  
14477 2026.06.22
2026.06.23
20 19 9 S13E41 0030 CRI DRI was AR S12168

SWPC spot number is unexpectedly high, typo?

S12169 2026.06.22       N17W40            
14478 2026.06.23
2026.06.24
16 34 22 S06E63 0825 FHC FKC beta-gamma-delta?

was AR S12170

area: 1440

location: S06E62

14479 2026.06.23
2026.06.24
4 10 4 N16E45 0020 CRO DRO was AR S12171

area: 0030

location: N16E44

S12172 2026.06.24       S05E34          
S12173 2026.06.24   2   N09W28 0004   AXX  
S12174 2026.06.25   1   N10E03 0002   AXX    
Total spot count: 66 153 68  
Sunspot number: 136 253 138  (total spot count + 10 * number of spotted regions)
Weighted SN: 95 188 103  (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): 150 139 110  

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
2025.03 163.7 162.1 134.2 135.9 (-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 91.7 106.7 (-1.6) 21.01
2025.12 160.8 155.8 124.0 (106.4 projected, -0.3) 13.35
2026.01 148.7 144.0 112.6 (102.7 projected, -3.7) 22.47
2026.02 136.4 133.1 78.2 (98.5 projected, -4.2) 12.88
2026.03 131.0 129.7 85.9 (93.9 projected, -4.6) 15.44
2026.04  120.0 120.9 79.3 (90.0 projected, -3.9) 12.10
2026.05 125.4 128.2 101.4 (88.7 projected, -1.3) 9.80
2026.06 128.1 (1)   82.5 (2A) / 99.0 (2B) / 116.9 (2C)
ISN preliminary average: 100.4
At this level SSN for December 2025
will become 107.1
(86.6 projected, -2.1) (10.0)
2026.07       (82.2 projected, -4.4)  
2026.08       (80.1 projected, -2.1)  
2026.09       (79.1 projected, -1.0)  
2026.10       (77.1 projected, -2.0)  
2026.11       (74.3 projected, -2.8)  

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.