The geomagnetic field was at quiet to active levels on October 28 under the influence of effects associated with CH1324. Solar wind speed at SOHO ranged between 383 and 482 km/sec, averaging 431 km/sec (+44 km/sec compared to the previous day). The high latitude magnetometer at Andenes recorded quiet to major 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
122.3 -
decreasing 61.7
over the previous solar rotation.
The 365 day average solar flux at 1 AU was 163.19 (183 days ago). The 81 day
average solar flux at 1 AU was 152.2 (41 days ago, this is 52.5% 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 20 (STAR Ap - based on the average of three hour interval ap indices: 19.5). Three hour interval K indices: 34324344 (planetary), 32333333 (Boulder), 45314356 (Andenes).
The background x-ray flux is at the class B4 level (GOES 19).
At the time of counting spots (see image time), spots were observed in 14 active regions using 2K resolution (SN: 251) and in 12 active regions using 1K resolution (SN: 167) SDO/HMI images.
AR 14257 [S09W71] was quiet and stable.
AR 14261 [S05W39] was quiet and stable.
AR 14262 [S13W72] decayed slowly and quietly.
AR 14264 [N10W38] reemerged with tiny spots.
AR 14266 [N16W23] developed slowly and quietly.
AR 14267 [N02E03] developed as new flux emerged to the north of the
largest penumbra. A small magnetic delta configuration formed and the region
could produce C and possibly minor M class flares. C1 flares: C1.6 @ 16:26
UT
AR 14269 [S11W00] decayed slowly and quietly.
AR 14270 [S07W17] decayed slowly and quietly.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S11555 [N09E40] was quiet and stable.
S11562 [S12E35] was quiet and stable.
S11564 [N14W07] was quiet and stable.
New AR S11565 [S03W23] emerged before noon, then decayed
slowly.
New AR S11566 [N05E22] was observed with tiny
spots in an old plage area.
New AR S11567 [S09E81] rotated into view.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
October 26-28: No obviously Earth directed CMEs observed in available coronagraph imagery.
[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 positive polarity southern hemisphere coronal hole (CH1324) will be Earth facing on October 26-29, CH1324 has decayed over the last solar rotation. A recurrent positive polarity trans equatorial coronal hole (CH1326) rotated across the central meridian on October 27, CH1326 has decayed significantly over the last rotation. A positive polarity northern hemisphere coronal hole (CH1327) could become Earth facing on October 29-30.
The geomagnetic field is expected to be at unsettled to minor storm levels on October 29 - November 2 due to effects associated with CH1324 with CH1326 contributing to the disturbance on October 30 and CH1327 on November 1-2.
| 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.
(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 | ||||||||||
| 14257 | 2025.10.17 | 1 | 1 | 1 | S09W73 | 0040 | HSX | HSX |
 |
 |
was AR S11534 location: S09W71 area: 0060 |
| 14262 | 2025.10.17 2025.10.20 |
3 | 3 | 2 | S14W73 | 0090 | CSO | DSO |
 |
 |
was AR S11536 area: 0160 location: S13W72 |
| 14259 | 2025.10.18 2025.10.19 |
S20W73 |
was AR S11539 location: S22W62 |
||||||||
| 14260 | 2025.10.18 2025.10.19 |
S11W63 |
was AR S11540 location: S12W47 |
||||||||
| 14261 | 2025.10.19 2025.10.20 |
1 | 3 | 1 | S05W41 | 0030 | HSX | CSO |
 |
 |
was AR S11543 area: 0060 location: S05W39 |
| 14264 | 2025.10.19 2025.10.21 |
2 | N07W51 | 0002 | BXO |
 |
was AR S11544 location: N10W38 |
||||
| S11547 | 2025.10.21 | N01W55 | |||||||||
| 14267 | 2025.10.22 2025.10.23 |
5 | 41 | 19 | N04W03 | 0110 | CSO | DHC |
 |
 |
beta-delta was AR S11549 area: 0310 location: N02E03 |
| 14266 | 2025.10.22 2025.10.23 |
5 | 19 | 10 | N16W25 | 0030 | CRO | DRI |
 |
 |
was AR S11550 area: 0070 location: N16W23 |
| 14268 | 2025.10.24 | S10W54 | the spots were part of AR 14260 | ||||||||
| 14269 | 2025.10.24 2025.10.25 |
3 | 11 | 5 | S11W00 | 0020 | CAO | DRO |
 |
 |
was AR S11554 area: 0050 |
| S11555 | 2025.10.25 | 5 | 2 | N09E40 | 0015 | CRO |
 |
 |
|||
| S11556 | 2025.10.25 | N19W25 | |||||||||
| S11557 | 2025.10.25 | N24W42 | |||||||||
| 14270 | 2025.10.26 2025.10.27 |
3 | 4 | 2 | S06W16 | 0010 | BXO | BXO |
 |
 |
was AR S11559 location: S07W17 |
| S11560 | 2025.10.26 | S30W07 | |||||||||
| S11562 | 2025.10.27 | 5 | 1 | S12E35 | 0010 | BXO |
 |
 |
|||
| S11563 | 2025.10.27 | S02E52 |
 |
||||||||
| S11564 | 2025.10.27 | 7 | 2 | N14W07 | 0015 | AXX |
 |
 |
|||
| S11565 | 2025.10.28 | 2 | S03W23 | 0003 | BXO |
 |
|||||
| S11566 | 2025.10.28 | 6 | 1 | N05E22 | 0013 | AXX |
 |
||||
| S11567 | 2025.10.28 | 2 | 1 | S09E81 | 0010 | HRX |
 |
||||
| Total spot count: | 21 | 111 | 47 | ||||||||
| Sunspot number: | 91 | 251 | 167 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 49 | 148 | 84 | (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): | 100 | 138 | 134 | ||||||||
| 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 | 141.8 (1) | 101.4 (2A) / 112.3 (2B) / 147.7 (2C) ISN month to date average: 119 At this level the April 2025 SSN will become 133.6 |
(111.5 projected, -4.0) | (14.6) | |
| 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
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.
--------------------------------------------------------------------------------------
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.
