Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 15, 2025 at 06:10 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 (October 1, 2025)
Solar cycle Solar cycles 23-25 (October 1, 2025) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (October 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 (October 1, 2025) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (October 1, 2025) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (August 17, 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 unsettled levels on October 14 under the weakening influence of effects associated with CH1322. Solar wind speed at SOHO ranged between 544 and 739 km/sec, averaging 636 km/sec (-57 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 154.4 - increasing 6.8 over the previous solar rotation.
The 365 day average solar flux at 1 AU was 165.13 (183 days ago). The 81 day average solar flux at 1 AU was 154.5 (41 days ago, this is 54.0% 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 7 (STAR Ap - based on the average of three hour interval ap indices: 6.9). Three hour interval K indices: 22212213 (planetary), 22212322 (Boulder), 44322224 (Andenes).

The background x-ray flux is at the class C3 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 13 active regions using 2K resolution (SN: 324) and in 9 active regions using 1K resolution (SN: 182) SDO/HMI images.

AR 14246 [N23W39] developed further. The spot group is compact and very complex with multiple magnetic delta configurations. An X class proton flare would not be a surprise. C1 flares: C1.7 @ 01:15, C1.8 @ 10:56 UT
AR 14248 [N06W06] decayed slowly and quietly. Note that SWPC/USAF made a mistake and swapped region numbers on October 12 for this AR and AR 14250. The original numbering will be kept here for data consistency and integrity reasons.
AR 14249 [S19W01] was quiet and stable.
AR 14250 [N07W13] developed as new flux emerged in the central spot section. A magnetic delta configuration formed there and the region could produce a major flare.
AR 14251 [N19E12] decayed slowly and quietly.
AR 14252 [S14E39] was quiet and stable.
AR 14253 [S16W35] decayed slowly and quietly.
New AR 14254 [N09E72] rotated into view on October 13 and was numbered the next day by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S11520 [N10E27] decayed slowly and quietly.
S11521 [N10W33] was quiet and stable.
S11522 [N12E02] decayed slowly and quietly.
S11525 [S23E37] was quiet and stable.
New AR S11526 [S08E67] emerged with tiny spots and is likely to develop further.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
M2.0 00:41 N25W25 14246 GOES18  
C2.1 01:41   14246 GOES18  
C2.4 01:44   14246 GOES18  
C2.0 02:46   14246 GOES18  
C4.2 03:04   14246 GOES18  
C4.3 03:16   14246 GOES18  
C2.5 03:36   14246 GOES18  
C3.4 04:14 N24W28 14246 GOES18  
C3.6 04:33   14246 GOES18  
C2.7 04:50   14248 GOES18  
C2.7 05:32   14248 GOES18  
C3.9 05:47 N25W31 14246 GOES18  
C2.6 06:22   14246 GOES18  
C2.7 06:35   14246 GOES18  
C2.6 06:38   14246 GOES18  
C2.7 07:01   14246 GOES18  
C2.9 07:16   14246 GOES18  
C3.6 07:36   14246 GOES18  
C3.5 07:48   14246 GOES18  
C2.8 08:09   14246 GOES18  
C2.8 08:26   14246 GOES18  
C6.0 08:46 N23W32 14246 GOES19  
C3.9 09:08   14246 GOES19  
C3.2 09:56   14246 GOES19  
C3.3 11:10 N22W34 14246 GOES18  
C3.5 11:15   14246 GOES18  
M2.0/1N 12:47   14250 GOES18 smaller, simultaneous flare in AR 14246
C8.2 13:23 N23W37 14246 GOES18  
C6.3 14:07   14246 GOES18  
C4.5 14:19   14246 GOES18  
C3.6 14:55 S12W74 14247 GOES18  
C3.2 15:20   14246 GOES18  
C5.0 15:40   14246 GOES18  
C2.6 16:13   14246 GOES18  
C3.1 16:24   14246 GOES18  
C3.2 16:40   14246 GOES18  
C3.7 17:11   14250 GOES18  
C3.8 17:16   14246 GOES18  
C3.8 17:19   14247 GOES18  
C3.5 17:27   14247 6GOES18  
C3.8 17:43   14246 GOES18  
C6.5 17:53   14246 GOES18  
C3.9 18:28   14246 GOES18  
C2.8 19:08   14246 GOES18  
C7.0 19:43   14246 GOES18  
C5.2 19:51   14246 GOES18  
C3.8 20:26 southeast limb   GOES18 (this region was the source of an M2.1 flare at 04:46 UT on Oct.15)
M3.1 20:36   14246 GOES18  
C5.9 21:11   14246 GOES18  
C7.8 21:43   14246 GOES18  
C6.7 21:51   14246 GOES18  
C6.3 22:07   14246 GOES18  
C5.2 22:21   14246 GOES18  
C3.4 22:57   14246 GOES18  
C2.4 23:20   14246 GOES18  
C4.3 23:42   14246 GOES18  
C5.3 00:05   14246 GOES18 flare began at 23:56 UT

Coronal mass ejections (CMEs)

October 13: A CME was observed in LASCO imagery after the M1.3 flare in AR 14246 at 13:18 UT. The CME could reach Earth on October 16.
October 12, 14
: No obviously Earth directed CMEs 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 negative polarity northern hemisphere coronal hole (CH1323) will become Earth facing on October 16-18.

Forecast

The geomagnetic field is expected to be at quiet to minor storm levels on October 15-17 due to CME effects. Quiet to unsettled is likely on October 18. October 19-21 could see quiet to minor storm levels due to effects associated with CH1323.

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
14244 2025.10.04
2025.10.05
      S21W64           was AR S11500

location: S21W55

14246 2025.10.05
2025.10.06
27 79 41 N22W43 0260 EKC EKC beta-gamma-delta

was AR S11505

area: 0780

location: N23W39

14247 2025.10.05
2025.10.07
      S12W78        

was AR S11506

location: S12W76

14249 2025.10.08
2025.10.09
  14 5 S20W08 0030   BXO was AR S11508

location: S19W01

S11509 2025.10.08       N30W32            
14248 2025.10.09
2025.10.10
16 13 7 N07W13 0300 EKI DRO area: 0030

location: N06W06

SWPC swapped data for ARs
14248 and 14250 starting 2025.10.12,
they now have the original 14248
as 14250.

14250 2025.10.09
2025.10.10
2 52 30 N07W07 0020 CRO EKC beta-gamma-delta

was AR S11511

area: 1000

location: N07W13

14251 2025.10.10
2025.10.12
1 5 2 N19E12 0010 AXX BXO was AR S11514

area: 0020

S11515 2025.10.10       N18W19          
14253 2025.10.11
2025.10.12
  1   S17W38 0001   AXX was AR S11516
14252 2025.10.11
2025.10.12
1 15 4 S13E38 0090 HSX CKO was AR S11517

area: 0310

location: S14E39

S11518 2025.10.12       S23E15            
S11519 2025.10.12       N08W44            
S11520 2025.10.12   1 1 N10E27 0003   AXX  
S11521 2025.10.13   3 1 N10W33 0005   BXO  
S11522 2025.10.13   3   N12E02 0005   BXO  
14254 2025.10.13
2025.10.14
1 1 1 N10E74 0040 HSX HSX was AR S11523

area: 0140

location: N09E72

S11524 2025.10.13       S04E46          
S11525 2025.10.13   4   S23E37 0006   BXO  
S11526 2025.10.14   3   S08E67 0003   BXO    
Total spot count: 48 194 92  
Sunspot number: 108 324 182  (total spot count + 10 * number of spotted regions)
Weighted SN: 81 232 130  (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): 119 178 146  

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
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
2024.10 221.0 219.6 165.8 160.9 (+1.5) (SC25 solar max) 18.99
2024.11 199.6 195.3 154.1 157.1 (-3.8) 9.33
2024.12 197.3 191.2 154.6 151.3 (-5.8) 8.42
2025.01 190.3 184.2 137.0 146.3 (-5.0) 13.17
2025.02  184.2 179.7 155.7 139.9 (-6.4) 14.42
2025.03 163.7 162.1 134.2 136.0 (-3.9) 15.96
2025.04 162.5 163.6 140.6 (133.7 projected, -2.3) 17.62
2025.05  135.3 138.3 79.2 (130.1 projected, -3.6) 17.26
2025.06 131.3 135.4 116.3 (126.3 projected, -3.8) 21.43
2025.07 137.8 142.3 125.6 (123.0 projected, -3.3) 11.80
2025.08 154.9 158.7 133.6 (119.4 projected, -3.6) 9.97
2025.09 154.4 156.0 129.6 (115.5 projected, -3.9) 14.1
2025.10 143.8 (1)   54.2 (2A) / 119.9 (2B) / 164.6 (2C) (111.5 projected, -4.0) (18.8)
2025.11       (109.3 projected, -2.2)  
2025.12       (107.6 projected, -1.7)  
2026.01       (103.5 projected, -4.1)  
2026.02       (99.4 projected, -4.1)  
2026.03       (95.0 projected, -4.4)  

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 June 23, 2025

Sunspot activity has been on a decreasing trend since September 2024 (using the average solar flux over 3 solar rotations as a proxy). Compared to the peak of SC25 solar flux has been at a low level in both May and June 2025. Taking a closer look at the 81 day (3 solar rotations) average solar flux proxy, its peak was in early September 2024 and had on May 12 decreased to less than half of the solar cycle flux range. Subtracting the 81 day average of approximately 69 at solar cycle minimum from all measurements, the SC25 range is 0 - 158.3.

All 365 day smoothed sunspot numbers peaked on October 11-12, 2024
, very likely making this the peak of SC25 (365 day smoothed peaks: STAR 1K: 236.1, STAR 2K: 364.3, NOAA SN: 156.0, ISN: 163.9). 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.