Weekly forecast

Forecast issued date:

Solar activity forecast for the period October 16 - October 22, 2026

Activity level: low to moderate
X-ray background flux (1.0-8.0 A): in the range B7.0-C2.0
Radio flux (10.7 cm): a fluctuation in the range: 105-140
Events: class C (0-6/day), class M (0-3/period), class X (0/period), proton (0/period)
Relative sunspot number (Ri): in the range 42-100

Martina Pavelkova
RWC Prague, Astronomical Institute, Solar Dept., Ondrejov, Czech Republic

Geomagnetic activity forecast for the period October 16 - October 22, 2026


Quiet:   Oct 16 - 20
Unsettled: Oct 15, 21 - 22
Active:  Oct 15, 21 - 22
Minor storm: possible about Oct 22
Major storm:  0
Severe storm: 0

At the Budkov observatory, last week, the local K-index reached level 6.
Next days, we expect, generally, geomagnetic activity decrease to unsettled (till Friday, October 16) and quiet level (October 16 - 20).
At the end of currently forecasted period, an another active event is possible about Thursday, October 22.

Tomas Bayer
RWC Prague
Institute of Geophysics of the ASCR, Prague
Department of Geomagnetism
Budkov observatory (BDV)

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere October 16 - October 22, 2026

The so-called 27-day recurrence—derived from the duration of one rotation of the Sun around its own axis—is often a useful tool for forecasting fluctuations in solar activity. Although rare, there are instances when the trend is exactly the opposite, which can be directly misleading for predicting future developments. The most recent peak solar flux of 136 s.f.u. on October 13 was measured exactly 27 days after September 17, when the flux was 97 s.f.u.—the first day of a relatively long interval with low values below 100 s.f.u. Consequently, the state of the Earth’s ionosphere—and thus shortwave propagation conditions—was not as favorable as might be expected at this time of year.

Furthermore, solar activity will decline for the remainder of October. Although a disturbance in the Earth’s geomagnetic field can be expected after October 20, it should be brief, and the rest of the month is expected to bring relatively calm and favorable conditions.

F. K. Janda, A.R.S. OK1HH
http://ok1hh.nagano.cz/
Emails: ok1hh(at)crk.cz, ok1hh(at)rsys.cz
Pmail: OK1HH(at)OK0NAG.#BOH.CZE.EU

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