October 2026 may bring several periods of increased geomagnetic activity, with the most interesting one so far emerging around October 21-24. This is shown by the current long-term forecast of the NOAA Space Weather Prediction Center, published on September 28.
However, for most of the month, the forecast currently does not show conditions for strong magnetic storms.
When is increased activity expected in October
The first more active period is expected between October 4 and 8. NOAA predicts a planetary Kp index of up to 4 on October 4, 5 and 6. This means an active geomagnetic situation, but still below the official threshold for a geomagnetic storm.
A more significant period is emerging between October 21 and 24. For October 21, the forecast Kp is 4, and on October 22 it reaches 5. It is Kp 5 that corresponds to the initial level G1 on the five-point scale for geomagnetic storms of NOAA. On October 23 and 24, the forecast again shows Kp around 4.
A new moderate increase in geomagnetic activity is expected for the end of the month, around October 31, but according to the current 45-day forecast, it does not reach the level of a magnetic storm.
These dates should not be perceived as a definitive “calendar of magnetic storms“. Long-term forecasts largely assume repeating patterns of solar activity, while a powerful new flare or coronal mass ejection can quickly change the forecast.
Why a magnetic storm can't be accurately predicted weeks in advance
Solar flares are powerful releases of energy from the Sun. The most intense ones fall into class X, followed by M, C, B, and A. But a strong solar flare doesn't automatically mean a strong magnetic storm on Earth.
Cornal mass ejections, in which huge amounts of plasma and magnetic field leave the Sun's atmosphere, are particularly important. If such an ejecta is directed towards Earth and its magnetic field interacts favorably with the Earth's magnetosphere, a geomagnetic storm may ensue.
Therefore, the exact strength of a given storm often becomes clear only relatively close to the arrival of the solar material.
The Sun continues to show a capacity for powerful eruptions and in 2026 NASA recorded several events of the highest X class, including X8.1 in February, X2.5 in April and X1.3 in July.
What do Kp 4, Kp 5 and higher values mean
The Kp index is one of the main indicators of the state of the Earth's magnetic field and moves on a scale from 0 to 9.
At Kp 0-2, the geomagnetic situation is relatively calm. Kp 3-4 indicates an elevated or active situation. At Kp 5, a G1 class geomagnetic storm begins, and as the index increases, the potential for more serious technological effects increases.
Strong geomagnetic storms can affect the operation of satellites, radio communications, navigation systems, and, in sufficiently powerful events, the power transmission infrastructure. NASA emphasizes that solar flares and other manifestations of space weather can also pose risks to spacecraft and astronauts.
Do magnetic storms affect health?
This is one of the topics around which there is the most speculation. Headaches, insomnia, fatigue, changes in blood pressure and palpitations are often attributed to magnetic storms, but scientific evidence for a direct causal relationship remains limited and contradictory.
The World Health Organization states more generally that the available evidence does not confirm adverse health effects from routine exposure to low levels of electromagnetic fields. There are individual epidemiological studies of possible links between geomagnetic activity and cardiovascular events, but such observations alone do not prove that magnetic storms are the cause.
Therefore, people with hypertension or cardiovascular disease should not change their medications or treatment based on online “magnetic storm calendars“. In case of unusual symptoms, the correct approach remains medical consultation.