Viewing archive of Saturday, 31 May 2025
Solar activity report
Report of Solar-Geophysical Activity 2025 May 31 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 151 Issued at 2200Z on 31 May 2025IA. Analysis of Solar Active Regions and Activity from 30-2100Z to 31-2100Z Solar activity has been at high levels for the past 24 hours.
There are currently 5 numbered sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is likely to be moderate
with a chance for X-class flares on days one, two, and three (01 Jun, 02
Jun, 03 Jun).
IIA. Geophysical Activity Summary 30-2100Z to 31-2100Z
The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed reached a peak of 822 km/s at 31/0518Z. Total IMF reached 7
nT at 31/0045Z. The maximum southward component of Bz reached -6 nT at
30/2248Z. Protons greater than 10 MeV at geosynchronous orbit reached a
peak level of 25 pfu at 31/2045Z. Electrons greater than 2 MeV at
geosynchronous orbit reached a peak level of 9162 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at active to severe storm levels on day one (01 Jun), minor storm
to severe storm levels on day two (02 Jun) and active to major storm
levels on day three (03 Jun). Protons are expected to cross threshold on
days one, two, and three (01 Jun, 02 Jun, 03 Jun).
III. Event Probabilities 01 Jun to 03 Jun
| Class M | 65% | 65% | 65% |
| Class X | 25% | 25% | 25% |
| Proton | 75% | 75% | 75% |
| PCAF | yellow | ||
IV. Penticton 10.7 cm Flux
Observed 31 May 164 Predicted 01 Jun-03 Jun 165/160/150 90 Day Mean 31 May 154
V. Geomagnetic A Indices
Observed Afr/Ap 30 May 018/016 Estimated Afr/Ap 31 May 014/018 Predicted Afr/Ap 01 Jun-03 Jun 052/096-055/100-031/044
VI. Geomagnetic Activity Probabilities 01 Jun to 03 Jun
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 05% | 15% | 30% |
| Minor storm | 40% | 35% | 35% |
| Major-severe storm | 55% | 55% | 25% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 01% | 01% | 05% |
| Minor storm | 05% | 05% | 15% |
| Major-severe storm | 95% | 95% | 80% |
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 | 117.9 -6.1 |
| Last 30 days | 121.2 +12.1 |