Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 2, 2026 at 02:15 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 (February 2, 2026)
Solar cycle Solar cycles 23-25 (February 1, 2026) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (February 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 (February 1, 2026) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (February 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 very quiet levels on February 1. Solar wind speed at SOHO ranged between 299 and 383 km/sec, averaging 347 km/sec (-78 km/sec compared to the previous day). The high latitude magnetometer at Andenes was at quiet to unsettled 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 161.5 - increasing 7.2 over the previous solar rotation.

The 365 day average solar flux at 1 AU was 150.71 (183 days ago). The 81 day average solar flux at 1 AU was 145.1 (41 days ago, this is 48.1% 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 4 (STAR Ap - based on the average of three hour interval ap indices: 3.8). Three hour interval K indices: 00111111 (planetary), 01111211 (Boulder), 00012223 (Andenes).

The background x-ray flux is at the class M1 level (GOES 19).

At the time of counting spots (see image time), spots were observed in 16 active regions using 2K resolution (SN: 277) and in 15 active regions using 1K resolution (SN: 213) SDO/HMI images.

AR 14355 [S17W58] decayed slowly and quietly.
AR 14357 [S12W79] decayed slowly and quietly.
AR 14358 [N15W03] developed slowly and quietly.
AR 14359 [N22W23] was quiet and stable.
AR 14360 [S14E02] was quiet and stable.
AR 14362 [S17E32] was quiet and stable.
AR 14363 [S26E35] developed slowly and quietly.
AR 14365 [N28W35] decayed slowly and quietly.
AR 14366 [N14E35] gained area and is a compact and complex region with two strong magnetic delta configurations in the central spot section. Further major flares are likely. The region was very unstable and produced many M flares and 2 X class events. Early on February 2 another two X class events were recorded.
AR 14367 [N08E60] was quiet and stable.
AR 14368 [S10E65] was quiet and stable.
New AR 14369 [S02E70] rotated into view on January 31 and was numbered the next day by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
AR S11814 [N11W33] was quiet and stable.
AR S11826 [S23W12] developed slowly and quietly.
New AR S11830 [S18E77] rotated into view with tiny and small spots.
New AR S11831 [S22E81] rotated into view with tiny spots.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.7 00:59   14366 GOES18  
C3.6 01:50   14366 GOES18  
M1.7 02:05   14366 GOES18  
C7.1 02:47   14366 GOES18  
C7.1 02:56   14366 GOES18  
M1.0 03:41   14366 GOES18  
C9.2 03:47   14366 GOES18  
C8.1 04:05 southeast limb S11831 GOES18  
M1.9 04:20   14366 GOES18  
M1.2 04:45   14366 GOES18 simultaneous flare in AR S11831
C7.8 05:08   14366 GOES18  
C8.3 05:12   14366 GOES18  
C4.0 05:41   14366 GOES18  
C2.8 06:22   14366 GOES18  
C2.9 06:39   14366 GOES18  
C5.4 07:08   14366 GOES18  
C5.4 07:23   14366 GOES18  
C5.3 07:36   14366 GOES18  
C5.5 07:49   14366 GOES18  
C4.3 08:29   14366 GOES18  
C3.2 08:48   14366 GOES18  
C3.7 09:03   14366 GOES18  
C4.2 09:50   14366 GOES18  
M6.6 10:02   14366 GOES18  
M2.8 10:13   14366 GOES18  
M2.4 10:40   14366 GOES18  
M1.3 11:56   14366 GOES18  
M2.5 12:02   14366 GOES18  
M6.7 12:12   14366 GOES18  
M6.5 12:27   14366 GOES18  
X1.0 12:33   14366 GOES18  
M5.8 12:50   14366 GOES18  
M1.2 13:59   14366 GOES18  
M1.0 14:09   14366 GOES18  
M1.5 14:25   14366 GOES18  
C6.3 15:20   14366 GOES18  
M1.5 15:48   14366 GOES18  
M5.1 16:05   14366 GOES18  
M1.1 16:44   14366 GOES18  
M1.1 16:51   14366 GOES18  
M1.1 17:35   14366 GOES18  
M2.5 17:58   14366 GOES18  
M2.1 18:19   14366 GOES18  
M1.5 18:29   14366 GOES18  
M1.9 18:56   14366 GOES18  
M1.8 19:22   14366 GOES18  
M2.2 20:30   14366 GOES18  
M1.7 20:49   14366 GOES18  
C6.6 22:29   14366 GOES18  
M1.4 23:27   14366 GOES18  
X8.1/3B 23:57   14366 GOES18 strong type II and moderate type IV radio sweeps

Coronal mass ejections (CMEs)

January 30-31: No obviously Earth directed CMEs were observed in available coronagraph imagery.
February 1-2: A relatively slow moving partial halo CME was observed after the 3 X flares in AR 14366 late on February 1 and early on February 2. The CME could reach Earth on February 4-5.

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 trans equatorial negative polarity coronal hole (CH1342) could rotate across the central meridian on February 3-4. CH1342 has become much smaller over the last rotation and appears to be decaying.

Forecast

The geomagnetic field is expected to be at mostly quiet levels on February 1-4.

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
14355 2026.01.21
2026.01.24
  4   S13W63 0005   BXO was AR S11798

location: S16W55

14365 2026.01.23
2026.01.30
  3 1 N26W39     BXO was AR S11806

location: N28W35

14361 2026.01.24
2026.01.28
      N19W84           was AR S11809

location: N18W78

S11813 2026.01.25       N17W43            
S11814 2026.01.26   1 1 N11W33 0003   AXX  
14357 2026.01.26
2026.01.27
1 2 1 S13W80 0010 AXX AXX was AR S11816

area: 0004

location: S12W79

14358 2026.01.26
2026.01.27
  13 5 N14W05 0020   CRO was AR S11817

location: N15W03

14360 2026.01.27
2026.01.28
  6 2 S16W01 0010   BXO was AR S11819

location: S15E02

14359 2026.01.27
2026.01.28
1 5 2 N22W23 0010 AXX BXO was AR S11820
14362 2026.01.28 1 7 3 S18E31 0040 HAX CAO was AR S11822

area: 0120

location: S17E32

14363 2026.01.28
2026.01.29
  11 4 S26E31 0020   BXO was AR S11823

location: S26E46

14366 2026.01.29
2026.01.30
21 47 32 N14E35 0550 EKC EKC beta-delta-gamma

was AR S11825

area: 1830

S11826 2026.01.29   5 3 S25W12 0020   BXO  
14367 2026.01.31
2026.01.31
1 3 1 N07E62 0030 HSX CAO was AR S11827

area: 0160

location: N08E60

14368 2026.01.31
2026.01.31
1 1 1 S10E63 0030 HSX HSX was AR S11828

area: 0220

location: S10E65

SWPC area is generally speaking way too low

14369 2026.01.31
2026.02.01
1 1 1 S01E71 0120   HSX was AR S11829

area: 0190

location: S02E70

S11830 2026.02.01   5 4 S18E77 0020   DRO    
S11831 2026.02.01   3 2 S22E81 0030   CRO    
Total spot count: 27 117 63  
Sunspot number: 97 277 213  (total spot count + 10 * number of spotted regions)
Weighted SN: 57 156 102  (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): 107 152 170  

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
2024.11 199.6 195.3 154.1 157.2 (-3.7) 9.33
2024.12 197.3 191.2 154.6 151.2 (-6.0) 8.42
2025.01 190.3 184.2 137.0 146.2 (-5.0) 13.17
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 (119.9 projected, -2.5) 9.97
2025.09 154.4 156.0 129.7 (117.2 projected, -2.7) 14.02
2025.10 139.5 138.6 114.6 (114.1 projected, -3.1) 15.64
2025.11 140.3 137.3 91.7 (112.4 projected, -1.7) 21.01
2025.12 160.8 155.8 124.0 (111.1 projected, -1.3) 13.35
2026.01 149.4 144.0 112.6 (107.2 projected, -3.9) 23.2
2026.02 161.5 (1)   3.5 (2A) / 97 (2B) / 140.9 (2C) (103.0 projected, -4.2) (3.8)
2026.03       (98.4 projected, -4.6)  
2026.04       (94.5 projected, -3.9)  
2026.05       (93.3 projected, -1.2)  
2026.06       (91.1 projected, -2.2)  
2026.07       (86.7 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 October 2025

Sunspot activity was on a decreasing trend from September 2024 until mid August 2025 (using the average solar flux over 3 solar rotations as a proxy). Then a strong surge in activity saw solar flux peak in late August 2025 just below the largest peaks seen in 2024. A slow decrease in activity from the August level has been observed in September and October 2025.

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.