Viewing archive of Thursday, 18 December 2025
Solar activity report
Report of Solar-Geophysical Activity 2025 Dec 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 352 Issued at 2200Z on 18 Dec 2025IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity has been at low levels for the past 24 hours.
There are currently 5 numbered sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is expected to be low with
a slight chance for an M-class flare on days one, two, and three (19
Dec, 20 Dec, 21 Dec).
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic
field has been at quiet to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 723 km/s at 18/0659Z. Total IMF
reached 7 nT at 17/2227Z. The maximum southward component of Bz reached
-7 nT at 17/2232Z. Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 2693 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to unsettled levels on days one and two (19 Dec, 20 Dec)
and quiet levels on day three (21 Dec).
III. Event Probabilities 19 Dec to 21 Dec
| Class M | 15% | 15% | 15% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Dec 116 Predicted 19 Dec-21 Dec 115/110/110 90 Day Mean 18 Dec 149
V. Geomagnetic A Indices
Observed Afr/Ap 17 Dec 010/018 Estimated Afr/Ap 18 Dec 014/018 Predicted Afr/Ap 19 Dec-21 Dec 009/010-008/008-005/005
VI. Geomagnetic Activity Probabilities 19 Dec to 21 Dec
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 20% | 10% |
| Minor storm | 10% | 05% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 25% | 25% | 20% |
| Major-severe storm | 35% | 25% | 10% |
All times in UTC
Latest news
Thursday, 4 June 2026
G3 geomagnetic storm watch for 4 and 5 June
Wednesday, 13 May 2026
Coronal hole faces Earth
Monday, 30 March 2026
X1.5 solar flare
Latest forum messages
AR4473 24Incoming & Unnumbered Active Regions 485How did you get into space weather? 63X alerts currently not available 6AR4472 20
More topicsSupport SpaceWeatherLive.com!
A lot of people come to SpaceWeatherLive to follow the Solar activity or if there is a chance to see the aurora, but with more traffic comes higher costs to keep the servers online. If you like SpaceWeatherLive and want to support the project you can choose a subscription for an ad-free site or consider a donation. With your help we can keep SpaceWeatherLive online!
Space weather facts
| Last X-flare | 2026/06/03 | X1.0 |
| Last M-flare | 2026/06/21 | M6.8 |
| Last geomagnetic storm | 2026/06/11 | Kp5 (G1) |
| Spotless days | |
|---|---|
| Last 365 days | 3 days |
| 2026 | 3 days (2%) |
| Last spotless day | 2026/02/24 |
| Monthly mean Sunspot Number | |
|---|---|
| May 2026 | 101.4 +22.1 |
| June 2026 | 98.3 -3.1 |
| Last 30 days | 107.4 +9 |
