Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 20, 2025 at 05:50 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, 2025)
Solar cycle Solar cycles 23-25 (June 1, 2025) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (June 1, 2025) 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, 2025) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (June 1, 2025) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (April 21, 2025) Cycle 25 spots (final update December 25, 2019)
  Solar cycles 24-25 transition using 365d smoothing Research: Solar Cycle 25 Started on November 17, 2019 with 365 Days Smoothing
Calculating the Strength of Solar Cycle 25 Using 365-day Smoothing

Recent activity

The geomagnetic field was at quiet to active levels on June 19 under the influence of effects associated with CH1301. Solar wind speed at SOHO ranged between 437 and 614 km/sec, averaging 499 km/sec (+9 km/sec compared to the previous day). The high latitude magnetometer at Andenes recorded 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 136.2 - increasing 15.4 over the previous solar rotation. The 365 day average solar flux at 1 AU was 187.48 (183 days ago). SC25 365d peak: 195.86 on October 13, 2024. The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.3). Three hour interval K indices: 21211243 (planetary), 32213243 (Boulder), 53201354 (Andenes).

The background x-ray flux is at the class B8 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 13 active regions using 2K resolution (SN: 246) and in 13 active regions using 1K resolution (SN: 184) SDO/HMI images.

AR 14111 [N15W65] decayed slowly and was mostly quiet. C1 flares: C1.6 @ 10:43 UT
AR 14114 [N19W37] decayed losing spots, area and magnetic delta configurations. There's still significant polarity intermixing. Apart from the X1 flare just before midnight, the region produced a number of C flares. C1 flares: C1.7 @ 01:30, C1.3 @ 02:16, C1.5 @ 02:53, C1.5 @ 03:22, C1.5 @ 06:06, C1.6 @ 11:00, C1.5 @ 13:34 UT
AR 14115 [N20W28] was mostly quiet and stable. The leader spot appears to maintain the same distance to the the largest spot in AR 14114. C1 flares: C1.8 @ 23:08 UT
AR 14116 [S11W30] decayed slowly and was mostly quiet.
AR 14117 [S14E51] decayed significantly during the day losing much of its magnetic complexity. Most of the flare activity occurred before noon. C1 flares: C1.4 @ 00:36, C1.5 @ 03:08, C1.5 @ 03:14, C1.7 @ 03:39, C1.9 @ 10:37, C1.8 @ 11:09, C1.2 @ 12:48 UT
New AR 14118 [S12E61] rotated into view on June 17 and was numbered by SWPC 2 days later. The region displayed slow decay with the large trailing penumbra splitting into smaller penumbrae.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S11163 [N23W31] decayed slowly and quietly.
S11165 [N14W12] reemerged with tiny spots.
S11168 [S02W73] was quiet and stable.
S11173 [N10E24] was quiet and stable.
New region S11175 [N08E12] emerged with a tiny spot before noon.
New region S11176 [N34W08] was observed with tiny spots in an old plage area.
New region S11177 [N13E35] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.5 04:12 S17E65 14117 GOES18  
C3.3 04:25   14117 GOES18  
C2.4 05:10   14117 GOES18  
C2.6 05:32   14117 GOES18  
C2.7 05:40   14117 GOES18  
C2.1 06:44   14117 GOES18  
C5.9 06:51 S13E63 14117 GOES18  
C6.0 07:27 N17W30 14114 GOES18  
C2.3 08:27 S15E64 14117 GOES18  
C8.0/1N 09:17 N17W32 14114 GOES18 simultaneous flare in AR 14117
C2.3 16:45   14114 GOES18  
C5.9 19:29 N19W35 14114 GOES18  
C2.2 20:48   14117 GOES18  
C4.4 21:34   14116 GOES18  
X1.9 23:50   14114 GOES18  

Coronal mass ejections (CMEs)

June 17-19: No obviously Earth directed CMEs.

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 large recurrent polar connected positive polarity southern hemisphere coronal hole (CH1301) will be Earth facing on June 11-19.

Forecast

The geomagnetic field is expected to be at quiet to active levels on June 19-21 due to effects associated with CH1301.

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
14111 2025.06.08
2025.06.09
2 4 2 N16W65 0070 HSX HAX beta-gamma

was AR S11139

area: 0120

location: N15W65

14112 2025.06.08       S09W89           was AR S11141
14113 2025.06.10
2025.06.11
      N10W50         was AR S11149
14114 2025.06.10
2025.06.11
32 45 22 N21W41 0400 EKC EHI beta-gamma

was AR S11150

area: 0480

location: N19W37

14115 2025.06.11
2025.06.12
5 8 3 N22W28 0120 ESO ESO was AR S11151

area: 0160

location: N20W28

14116 2025.06.12
2025.06.14
2 5 3 S10W44 0040 HSX CSO was AR S11157

location: S11W43

area: 0060

S11159 2025.06.13       S03W31            
S11160 2025.06.14       S15W53            
S11162 2025.06.14       N21W16            
S11163 2025.06.15   6 3 N23W31 0013   BXO  
S11164 2025.06.16       N22W55            
S11165 2025.06.16   5 1 N14W12 0008   BXO    
14117 2025.06.17
2025.06.18
9 20 10 S14E50 0210 DAI EAO

was AR S11167

location: S14E51

area: 0330

S11168 2025.06.17   5 2 S02W73 0010   BXO  
S11169 2025.06.17       S09E09            
14118 2025.06.17
2025.06.19
3 6 3 S14E62 0050 DAO EAO was AR S11170

location: S12E61

area: 0300

S11171 2025.06.18       N26W27          
S11173 2025.06.18   3 2 N10E24 0006   BXO  
S11174 2025.06.18       N07W22          
S11175 2025.06.19   1 1 N08E12 0004   AXX    
S11176 2025.06.19   3 1 N34W08 0007   AXX    
S11177 2025.06.19   5 1 N13E35 0010   BXO    
Total spot count: 53 116 54  
Sunspot number: 113 246 184  (total spot count + 10 * number of spotted regions)
Weighted SN: 88 151 89  (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): 124 135 147  

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2024.01 164.6 159.3 126.0 131.2 (+1.7) 5.46
2024.02 172.5 168.3 123.0 136.9 (+5.7) 5.31
2024.03 154.4 152.9 103.7 141.4 (+4.5) 11.03
2024.04 161.3 162.6 137.0 144.5 (+3.1) 9.69
2024.05 187.7 191.9 172.1 149.1 (+4.6) 23.56
(SC25 peak)
2024.06 184.3 190.2 164.1 152.8 (+3.7) 10.24
2024.07 196.6 203.0 196.8 155.0 (+2.3) 7.13
2024.08  246.1
(cycle peak)
252.2 216.0  (SC25 peak) 156.8 (+1.8) 15.96
2024.09 195.7 197.8 141.1 159.4 (+1.6) 15.36
2024.10 221.0 219.6 165.8 160.8 (+1.4) (SC25 solar max) 18.99
2024.11 199.6 195.3 154.1 157.0 (-3.8) 9.33
2024.12 197.3 191.2 154.6 (150.7 projected, -6.3) 8.42
2025.01 190.3 184.2 137.0 (144.2 projected, -6.5) 13.17
2025.02  184.2 179.7 154.6 (135.6 projected, -8.6) 14.42
2025.03 163.7 162.1 134.2 (129.2 projected, -6.4) 15.96
2025.04 162.5 163.6 140.6 (124.6 projected, -4.6) 17.62
2025.05  135.3 138.3 79.2 (119.3 projected, -5.3) 17.26
2025.06 136.4 (1)   68.3 (2A) / 107.8 (2B) / 127.9 (2C) (114.4 projected, -4.9) (26.6)
2025.07       (110.2 projected, -4.2)  
2025.08       (105.5 projected, -4.7)  
2025.09       (101.2 projected, -4.3)  
2025.10       (97.3 projected, -3.9)  
2025.11       (95.0 projected, -2.3)  

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 May 13, 2025

Sunspot activity has been on a slowly decreasing trend since September 2024 (using the average solar flux over 3 solar rotations as a proxy). The decline has become more obvious during the first half of May 2025 with solar flux on May 12 at its lowest level since April 4, 2024. The solar max phase of solar cycle 25 was considerably shorter than that of the most recent solar cycles.

All 365 days smoothed sunspot numbers peaked on October 11-12, 2024
, very likely making this the peak of SC25 (STAR 1K 365d peak: 236.1, STAR 2K 365d peak: 364.3, NOAA SN 365d peak: 156.0, ISN 365d peak: 163.6). 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.