Viewing archive of Monday, 18 August 2025
Solar activity report
Report of Solar-Geophysical Activity 2025 Aug 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 230 Issued at 2200Z on 18 Aug 2025IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity has been at very low levels for the past 24
hours. There are currently 6 numbered sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is expected to be very low
with a chance for a C-class flares on days one and two (19 Aug, 20 Aug)
and likely to be low with a slight chance for an M-class flare on day
three (21 Aug).
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 414 km/s at 18/0603Z. Total IMF reached 11
nT at 18/1036Z. The maximum southward component of Bz reached -7 nT at
18/1058Z. Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 2222 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at unsettled to minor storm levels on days one and two (19 Aug, 20
Aug) and quiet to active levels on day three (21 Aug).
III. Event Probabilities 19 Aug to 21 Aug
| Class M | 05% | 05% | 10% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Aug 114 Predicted 19 Aug-21 Aug 112/108/110 90 Day Mean 18 Aug 136
V. Geomagnetic A Indices
Observed Afr/Ap 17 Aug 007/ 005 Estimated Afr/Ap 18 Aug 008/010 Predicted Afr/Ap 19 Aug-21 Aug 018/028-018/025-012/015
VI. Geomagnetic Activity Probabilities 19 Aug to 21 Aug
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 35% | 35% | 30% |
| Minor storm | 30% | 25% | 15% |
| Major-severe storm | 10% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 05% | 10% | 15% |
| Minor storm | 20% | 25% | 30% |
| Major-severe storm | 65% | 55% | 40% |
All times in UTC
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Space weather facts
| Last X-flare | 2025/12/01 | X1.9 |
| Last M-flare | 2025/12/04 | M6.0 |
| Last geomagnetic storm | 2025/12/04 | Kp5 (G1) |
| Spotless days | |
|---|---|
| Last spotless day | 2022/06/08 |
| Monthly mean Sunspot Number | |
|---|---|
| November 2025 | 91.8 -22.8 |
| December 2025 | 186 +94.2 |
| Last 30 days | 106.4 +13.7 |