NOAA forecasts moderate geomagnetic activity for late September 2026

The NOAA Space Weather Prediction Center has issued forecasts regarding geomagnetic activity for late September 2026. For September 26, the maximum expected three-hour planetary Kp index is 3.67, which remains below the threshold for a G1 category geomagnetic storm on the five-point scale.

While there is a 40% probability of active geomagnetic conditions on September 26, the official expectation is that activity will remain below G1 levels. The predicted daily Ap index is 12. No significant transient or recurring structures in the solar wind are expected to cause serious geomagnetic disturbances.

Earlier reports for September 25 indicated higher levels of geomagnetic activity. Experts note that such fluctuations can impact individuals with chronic or cardiovascular conditions, potentially causing headaches, blood pressure fluctuations, or insomnia. Medical professionals suggest that those with hypertension monitor their health closely during periods of geomagnetic disturbance.