Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 4, 2025 at 05:55 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 (January 1, 2025)
Solar cycle Solar cycles 23-25 (February 1, 2025) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (February 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 (February 1, 2025) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (February 1, 2025) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (January 11, 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 very quiet levels on February 3 as the IMF Bz component was northwards all day under the influence of the January 30 CME. Solar wind speed at SOHO ranged between 441 and 676 km/sec, averaging 510 km/sec (+46 km/sec compared to the previous day). The high latitude magnetometer at Andenes recorded very quiet 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 220.5 - increasing 52.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 193.21. In comparison SC24 peaked on June 28, 2014 at 145.50 while SC23 peaked on February 23, 2002 at 198.15. Current SC25 peak: 193.21 on August 5, 2024 (given a base solar flux level of 65, this is +59.27% compared to the SC24 peak and -3.71% compared to the SC23 peak). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.6). Three hour interval K indices: 10110001 (planetary), 11012212 (Boulder), 10000001 (Andenes).

The background x-ray flux is at the class C3 level (GOES 18).

At the time of counting spots (see image time), spots were observed in 19 active regions using 2K resolution (SN: 482) and in 14 active regions using 1K resolution (SN: 280) SDO/HMI images.

AR 13974 [S17W32] decayed slowly and quietly.
AR 13976 [N12W12] decayed slowly and was mostly quiet.
AR 13977 [N18W14] lost the magnetic delta configuration. There's still significant polarity intermixing and an M flare is possible.
AR 13978 [N11W01] decayed further and was mostly quiet.
AR 13979 [S09W82] decayed slowly and was mostly quiet.
AR 13980 [S10E07] was quiet and stable.
AR 13982 [N21E05] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S10753 [N06E18] decayed slowly and quietly.
S10755 [N16W02] decayed slowly and was mostly quiet.
S10756 [S13E00] reemerged with tiny spots.
S10759 [N07E10] developed further and has strong magnetic shear in the southern part of a trailing penumbra as well as a significant magnetic delta in the intermediate spot section. X class flaring is possible. This is the spot group SWPC currently has as AR 13981.
S10762 [N11E08] decayed slowly and quietly.
S10763 [N22E34] developed slowly and quietly.
S10764 [N21W29] was quiet and stable.
S10766 [S22E46] was quiet and stable.
New region S10768 [N20E28] emerged with tiny spots.
New region S10769 [N07E75] rotated into view with a mature spot.
New region S10770 [N25E31] emerged with tiny spots.
New region S10771 [S26W44] emerged with a tiny spot.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C6.3 00:39   S10759 GOES16  
C7.9 00:56   S10759 GOES16  
C6.3 01:28   S10759 GOES16  
C6.4 01:40   S10759 GOES16  
C6.0 02:12   S10759 GOES16  
C4.6 02:25   S10759 GOES16  
C4.0 02:46   S10759 GOES16  
C4.6 02:57   S10759 GOES16  
C4.5 03:14   S10759 GOES16  
M1.0 03:47   S10759 GOES16  
M8.8 03:58   S10759 GOES16  
M2.3 04:09   S10759 GOES16  
M1.1 04:32   S10759 GOES16 simultaneous flare in AR 13979
C7.2 05:08   S10759 GOES16  
C7.5 05:21   13979 GOES16  
C7.0 05:27   S10759 GOES16  
M3.1 05:47   S10759 GOES16  
C6.0 06:16   13977 GOES16  
C4.4 07:13     GOES16  
C4.8 07:25     GOES16  
M2.5 07:44   S10759 GOES16  
C6.1 08:49   S10759 GOES16  
C7.3 09:06   S10759 GOES16  
M1.4 09:13 N05E20 S10759 GOES16  
C8.0 09:19   S10759 GOES16  
C8.4 09:31   S10759 GOES16  
C8.7 09:39   13977 GOES16  
C9.4 09:58   S10755 GOES16  
C9.5 10:19   S10759 GOES16 simultaneous flare in AR 13977
C7.1 11:03 N15W07 S10759 GOES16 simultaneous flare in ARs 13978 / 13979
C7.1 11:21   S10759 GOES16  
C5.6 11:34   S10759 GOES16  
C9.5 11:47   S10759 GOES16  
C7.7 12:10   S10759 GOES16  
C5.8 12:31   S10759 GOES16  
C7.2 12:44   S10759 GOES16 multiple flare centers
M6.1 13:18   S10759 GOES16  
C4.7 14:39   S10759 GOES16  
C4.8 15:09   S10759 GOES16  
C4.6 15:32   S10759 GOES16  
C6.5 15:45   S10759 GOES16  
C3.3 16:28   S10759 GOES16  
C4.8 16:54   S10759 GOES16  
C5.0 17:02   S10759 GOES16  
C9.4 17:25   S10759 GOES16 multiple flare centers, simultaneous flare in AR 13979
C8.4 17:31   S10759 GOES16  
M4.3/2B 18:36 N07E15 S10759 GOES16  
M3.0 18:41   S10759 GOES16 simultaneous flare in AR 13979
C8.3 19:01   S10759 GOES16  
C8.4 19:05   S10759 GOES16  
C3.9 19:34   S10759 GOES16  
C4.3 19:44   S10759 GOES16  
C3.3 20:12   S10759 GOES16  
C4.5 20:42   S10759 GOES16  
M1.4 21:12   S10759 GOES16 simultaneous flare in AR 13977
C5.9 21:35   S10759 GOES16 simultaneous flare in AR 13976
C4.0 21:54   S10759 GOES16  
M1.4 23:28   S10759 GOES16  
C5.2 23:59 behind SE limb   GOES16  

Coronal mass ejections (CMEs)

February 1-3: 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 positive polarity trans equatorial coronal hole (CH1268) was Earth facing on January 28 - February 1. A recurrent negative polarity trans equatorial coronal hole (CH1269) will likely rotate across the central meridian on February 6-7.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be mostly quiet on February 4-7.

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
13974 2025.01.25
2025.01.26
9 12 4 S17W34 0010 BXO CRO    

was AR S10740

area: 0030

location: S17W32

SWPC spot count and area are incompatible

13976 2025.01.27
2025.01.27
21 49 24 N13W12 0260 EKI EAI     beta-gamma

location: N12W12

nearly all SWPC region spot counts are equal to the previous day

13977 2025.01.27
2025.01.27
12 45 25 N19W14 0120 DAI DAI     beta-gamma

area: 0250

location: N18W14

S10746 2025.01.27       N16W26            
13979 2025.01.27
2025.01.29
2 3   S10W83 0010 BXO BXO    

was AR S10747

location: S09W82

S10749 2025.01.27       S20W50            
13978 2025.01.28
2025.01.28
10 21 10 N11W02 0200 DAI DAO    

area: 0270

location: N11W01

13980 2025.01.29
2025.01.30
1 11 3 S10E05 0010 AXX BXO     was AR S10752

area: 0020

location: S10E07

S10753 2025.01.29   21 6 N06E18 0050   CAO     reinstated on 2025.02.02 due to SWPC using AR 13981 for two different spot groups
13981 2025.01.30 15     N05E09 0250 EKC       see AR S10753/S10759

This was initially AR S10753. SWPC moved the location of AR 13981 to that of AR S10759, a separate spot group which emerged on January 31.

13982 2025.01.30 3 8 2 N22E05 0030 CAO CRO     was AR S10754

no spots with mature penumbra

area: 0020

location: N21E05

S10755 2025.01.30   33 20 N16W02 0200   DAI      
S10756 2025.01.30   6 2 S13E00 0015   BXO      
S10757 2025.01.30       S04W26            
S10759 2025.01.31   55 33 N07E10 0950   EKC     beta-gamma-delta

This is currently AR 13981 to SWPC

S10760 2025.01.31       N02W54            
S10761 2025.01.31       S18W11            
S10762 2025.02.01   6 3 N11E08 0020   BXO      
S10763 2025.02.01   7 6 N22E34 0025   CRO      
S10764 2025.02.01   4   N21W29 0007   AXX      
S10766 2025.02.02   4   S22E46 0006   BXO      
S10767 2025.02.02       S20E26            
S10768 2025.02.03   2 1 N25E31 0005   BXO      
S10769 2025.02.03   2 1 N07E75 0080   HSX      
S10770 2025.02.03   2   N25E31 0003   BXO      
S10771 2025.02.03   1   S26W44 0001   AXX      
Total spot count: 73 292 140  
Sunspot number: 153 482 280  (total spot count + 10 * number of spotted regions)
Weighted SN: 108 341 189  (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): 168 265 224  

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2014.02 170.3
(cycle peak)
166.3 146.1 (SC24 peak) 110.5 10.70
2014.04 143.9 144.8 112.5 116.4 (SC24 solar max) 7.88
2017.09 91.3 92.3 43.6 18.2 (-1.3) 18.22
(SC24 peak)
2019.11 70.2 68.7 0.5 2.0 (-0.6)
(Solar minimum using 365d smoothing:
November 17, 2019)
4.19
2019.12 70.8 68.6 1.6 1.8 (-0.2)
(ISN 13 months smoothed
solar minimum)
3.22
2023.04 145.4 146.4 97.6 122.9 (+1.8) 13.40
2023.05 155.6 159.2 137.4 124.2 (+1.3) 10.67
2023.06 161.7 166.8 160.5 125.3 (+1.1) 8.95
2023.07  176.4 182.2 160.0 124.6 (-0.7) 8.15
2023.08  153.7 157.6 114.8 124.3 (-0.3) 7.19
2023.09  154.4 156.0 134.2 124.0 (-0.3) 14.26
2023.10  142.8 141.9 99.4 124.8 (+0.8) 8.16
2023.11 153.5 150.2 105.4 127.9 (+3.1) 12.20
2023.12 151.1 146.4 114.2 129.5 (+1.6) 9.60
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)
2024.06 184.3 190.2 164.1 152.7 (+3.6) 10.24
2024.07 196.6 203.0 196.8 154.9 (+2.3) 7.13
2024.08  246.1
(cycle peak)
252.2 216.0  (SC25 peak) (156.2 projected, +1.3) 15.96
2024.09 195.7 197.8 141.1 (158.3 projected, +2.1) 15.36
2024.10 221.0 219.6 166.3 (159.1 projected, +0.8) 18.99
2024.11 199.6 195.3 152.5 (156.5 projected, -2.6) 9.33
2024.12 197.3 191.2 154.5 (152.1 projected, -4.4) 8.42
2025.01 190.3 184.2  137.0 (145.8 projected, -6.3) 13.3
2025.02  208.0 (1)   16.2 (2A) / 151.3 (2B) / 161.3 (2C) (137.2 projected, -8.6) (14.9)
2025.03       (130.8 projected, -6.4)  
2025.04       (126.2 projected, -4.6)  
2025.05       (120.9 projected, -5.3)  
2025.06       (115.6 projected, -5.3)  
2025.07       (110.9 projected, -4.7)  

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 December 30, 2024

Sunspot activity increased again during the second half of December 2024, and this will be the eighth consecutive month with average solar flux above 180. The average solar flux at 1 AU since May 1, 2024 is 205. There is an increasing chance solar cycle 25 could have a higher 1 year solar flux average than solar cycle 23. The above plot displays a projected peak for the ISN 365d smoothed sunspot number on October 12, 2024. All the other smoothed sunspot numbers as well as the smoothed 365d solar flux have projected peaks October 12-15. A sudden decrease in activity during the first months of 2025 could move the SC25 max to sometime between July and October 2024.

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This report has been prepared by Jan Alvestad. It is based on the analysis of data from whatever 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.