Magnetic activity on July 13–14: quiet days following a strong storm

Forecasts for magnetic activity on July 13 and 14 show that after a stronger geomagnetic episode at the beginning of the month, calmer days are emerging, with no serious magnetic storms expected. The data comes from specialized space weather centers and scientific institutions that monitor geomagnetic activity indices and solar radiation in real time.

The Laboratory of Solar Astronomy (XRAS) has published a table with forecast values for the Ap index (characterizing the general level of geomagnetic agitation) and the F10.7 radio flux – a key indicator of solar activity – for the period of July 12–14, 2026. According to this data, the Ap index decreases sequentially from 24 on July 12 to 10 on July 13 and 6 on July 14, while the F10.7 remains in the range of 105 to 115 units, which corresponds to moderate solar activity with no preconditions for strong storms.

XRAS points out that the initially increased activity on July 12, reflected in an Ap value of 24, is gradually weakening, and the forecast for July 13 and 14 indicates a transition toward the normalization of the geomagnetic field. Lower Ap index values (10 and 6) are usually associated with quiet to slightly disturbed conditions and do not fall into the range of significant magnetic storms. This means that no G2–G5 class events on the NOAA scale, which are characteristic of more serious geomagnetic impacts, are expected for the two days.

A similar picture is seen in the specialized Bulgarian resource "Vreme & Radar" ("Weather & Radar"), where forecast values for the Kp index – a widely used indicator of geomagnetic activity – are published. According to the three-day forecast, a G1 class storm with a Kp of about 5 is recorded on July 12, while for July 13 the indicator drops to 3 ("disturbed" activity), and for July 14 – to 2 ("weakly disturbed"), which means minimal impact on people and their daily activities.

The same forecast emphasizes that on July 13, with a Kp of about 3, slight fatigue or malaise is possible in people sensitive to magnetic fluctuations, but no mass complaints or serious health risks are expected. For July 14, with a Kp of about 2, the influence is assessed as minimal, which means that the geomagnetic activity is practically approaching normal background levels and should not cause noticeable effects.

At the same time, the Bulgarian National Institute of Geophysics, Geodesy and Geography at the BAS publishes real-time observed and forecast values for the Kp index, providing a clear classification: "quiet" at Kp < 4, "active" at 4 ≤ Kp < 5, and "storm" at Kp ≥ 5. Current data for the day shows that the index has been moving around 3 in the last few hours, and the short-term forecast for the coming hours shows values around 2–2.33, confirming the trend toward relatively quiet geomagnetic conditions.

It is important to note that this quieter period of July 13–14 comes shortly after a strong geomagnetic episode at the beginning of the month, when international space weather centers reported the strongest magnetic storm of 2026 so far. According to information cited by Bulgaria ON AIR, a geomagnetic storm caused by a powerful solar flare lasted about 24 hours and was rated as the strongest since January. This event led to temporarily higher activity, which is gradually subsiding in the following days, as seen from the decline in Ap and Kp indices at the beginning of the second ten-day period.

From a statistical point of view, Kp values in the 0–3 range are considered normal or slightly disturbed; such days make up the majority of annual geomagnetic activity charts and are rarely associated with stronger physiological or technical effects. With an Ap index below 20, the situation is considered low to moderate excitation, and in the case of July 13 and 14, the values of 10 and 6 clearly show the absence of serious disturbances in the Earth's magnetic field.

For people who track magnetic storms for health reasons – for example, those with chronic illnesses or those who are weather-sensitive – experts recommend paying attention primarily to days with Kp ≥ 5 and Ap over 30, which refer to G1 class storms and above. For July 13 and 14, actual measurements and official forecasts do not show these levels being reached, which means the period can be described as relatively favorable from a space weather perspective.

In conclusion, available data from international and Bulgarian sources on magnetic activity for July 13–14 point to the absence of strong geomagnetic storms. On July 13, slight disturbances are expected (Kp around 3), and on July 14 – an even calmer situation (Kp around 2), accompanied by low Ap index values and moderate F10.7 solar radio flux. For most people, this means normal days without serious influence from space weather, with attention remaining focused mainly on those more sensitive to such changes.