Viewing archive of Friday, 17 October 2025
Solar activity report
Report of Solar-Geophysical Activity 2025 Oct 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 290 Issued at 2200Z on 17 Oct 2025IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z Solar activity has been at high levels for the past 24 hours.
There are currently 8 numbered sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is likely to be moderate
with a slight chance for an X-class flare on days one and two (18 Oct,
19 Oct) and expected to be low with a chance for M-class flares on day
three (20 Oct).
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 440 km/s at 16/2119Z. Total IMF reached 13
nT at 17/1025Z. The maximum southward component of Bz reached -8 nT at
17/0935Z. Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 3331 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to active levels on days one and two (18 Oct, 19 Oct) and
unsettled to active levels on day three (20 Oct). Protons greater than
10 Mev have a slight chance of crossing threshold on days one and two
(18 Oct, 19 Oct).
III. Event Probabilities 18 Oct to 20 Oct
| Class M | 60% | 60% | 40% |
| Class X | 15% | 15% | 05% |
| Proton | 10% | 10% | 05% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 17 Oct 164 Predicted 18 Oct-20 Oct 165/155/160 90 Day Mean 17 Oct 154
V. Geomagnetic A Indices
Observed Afr/Ap 16 Oct 003/004 Estimated Afr/Ap 17 Oct 013/016 Predicted Afr/Ap 18 Oct-20 Oct 013/016-012/012-012/014
VI. Geomagnetic Activity Probabilities 18 Oct to 20 Oct
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 35% | 35% | 35% |
| Minor storm | 15% | 10% | 10% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 15% | 10% |
| Minor storm | 25% | 30% | 30% |
| Major-severe storm | 50% | 45% | 45% |
All times in UTC
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Space weather facts
| Last X-flare | 2026/01/18 | X1.9 |
| Last M-flare | 2026/01/21 | M3.4 |
| Last geomagnetic storm | 2026/01/22 | Kp5+ (G1) |
| Spotless days | |
|---|---|
| Last spotless day | 2022/06/08 |
| Monthly mean Sunspot Number | |
|---|---|
| December 2025 | 124 +32.2 |
| January 2026 | 114.4 -9.6 |
| Last 30 days | 118.1 +9.1 |