Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 21, 2025 at 07:00 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 unsettled levels on June 20 under the influence of effects associated with CH1301. Solar wind speed at SOHO ranged between 465 and 649 km/sec, averaging 532 km/sec (+33 km/sec compared to the previous day). The high latitude magnetometer at Andenes recorded quiet to active 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 129.7 - increasing 0.0 over the previous solar rotation. The 365 day average solar flux at 1 AU was 187.28 (183 days ago). SC25 365d peak: 195.86 on October 13, 2024. The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.3). Three hour interval K indices: 22322321 (planetary), 13323321 (Boulder), 44324432 (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: 162) and in 8 active regions using 1K resolution (SN: 117) SDO/HMI images.

AR 14111 [N15W79] decayed slowly and quietly.
AR 14114 [N19W50] decayed further and was much less active than over the previous days. C1 flares: C1.1 @ 13:04 UT
AR 14115 [N20W41] was mostly quiet and stable.
AR 14116 [S11W56] decayed slowly and quietly.
AR 14117 [S15E37] was mostly quiet and stable with the only notable event an M1 flare in the afternoon.
AR 14118 [S12E61] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S11166 [S12W09] reemerged with tiny spots.
S11173 [N07E05] was quiet and stable.
New region S11178 [S03W28] was observed with tiny spots in an old plage area.

AR S11168 produced a C1.2 flare at 02:05 and C1.1 flare at 09:02 UT while near the southwest limb.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
M4.6/1N 00:04 N19W39 14114 GOES18  
C3.6 15:04 N16W53 14114 GOES18  
M1.0/1F 17:40 S12E46 14117 GOES18  
C2.1 18:41 behind SE limb   GOES18  
C2.2 18:48 behind SE limb   GOES18  

Coronal mass ejections (CMEs)

June 18-20: 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) was Earth facing on June 11-19. A small recurrent negative polarity trans equatorial coronal hole (CH1303) was Earth facing on June 20 and early on June 21. A large recurrent negative polarity trans equatorial coronal hole (CH1302) will likely rotate across the central meridian on June 22-24.

Forecast

The geomagnetic field is expected to be at quiet to unsettled levels on June 21 due to effects associated with CH1301. Quiet levels are likely on June 22-23. Quiet to active is possible on June 24 due to effects from CH1303 while effects associated with CH1302 could cause unsettled to minor storm conditions on June 25-27.

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
1 2 1 N14W78 0020 HSX HAX

was AR S11139

area: 0070

location: N15W79

14113 2025.06.10
2025.06.11
      N10W64           was AR S11149
14114 2025.06.10
2025.06.11
20 25 11 N18W54 0270 EKC EKI

was AR S11150

area: 0460

location: N19W50

14115 2025.06.11
2025.06.12
5 11 8 N22W41 0070 ESO ESO was AR S11151

area: 0180

location: N20W41

14116 2025.06.12
2025.06.14
1 2 1 S12W57 0010 HSX HAX was AR S11157

location: S11W56

area: 0060

S11159 2025.06.13       S03W44            
S11162 2025.06.14       N21W29            
S11163 2025.06.15       N23W44            
S11165 2025.06.16       N14W25          
S11166 2025.06.16   2 1 S12W09 0008   CRO    
14117 2025.06.17
2025.06.18
6 17 10 S14E38 0080 DAI DKO

was AR S11167

location: S15E37

area: 0360

SWPC area does not represent physical reality

S11168 2025.06.17       S02W86          
S11169 2025.06.17       S09W04            
14118 2025.06.17
2025.06.19
2 9 4 S13E50 0020 HSX EAO was AR S11170

location: S12E48

area: 0300

SWPC area does not represent physical reality

S11171 2025.06.18       N26W40            
S11173 2025.06.18   2 1 N07E05 0003   AXX  
S11174 2025.06.18       N07W35            
S11175 2025.06.19       N08W01          
S11176 2025.06.19       N34W21          
S11177 2025.06.19       N13E22          
S11178 2025.06.20   2   S03W28 0003   AXX    
Total spot count: 35 72 37  
Sunspot number: 95 162 117  (total spot count + 10 * number of spotted regions)
Weighted SN: 70 115 80  (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): 105 89 94  

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
2025.06 136.1 (1)   71.5 (2A) / 107.2 (2B) / 126.7 (2C) (114.4 projected, -4.9) (25.8)
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.