Space weather

How to read space weather data?

Space weather describes changes occurring on the Sun, in the solar wind, and in Earth's surroundings. Its effects can include geomagnetic storms and the appearance of the aurora, among other things. However, there is no single indicator that describes the entire situation. To understand what is happening between the Sun and Earth, it is worth monitoring several types of data at the same time.

Solar flares are sudden increases in energy emission in the Sun's atmosphere. Based on X-ray radiation, they are classified as A, B, C, M, and X. The higher the class, the stronger the flare. However, a strong flare does not automatically mean that a geomagnetic storm or aurora will occur on Earth.

Sunspots are cooler, darker areas of the photosphere associated with strong magnetic fields. They often form larger active regions where flares and other violent phenomena can occur. Observing the number and structure of such regions helps track the Sun's current activity.

Matter and magnetic fields are carried from the Sun toward Earth by the solar wind. Its speed, density, and magnetic field parameters, such as Bz and Bt, help assess how strongly the solar wind may interact with Earth's magnetosphere. Sustained negative Bz values can be particularly important, as they promote the transfer of energy into the magnetosphere.

The Kp index describes the level of global disturbances in Earth's magnetic field over successive 3-hour periods. Higher values indicate stronger geomagnetic activity and are usually associated with the possibility of the auroral oval shifting toward lower latitudes.

If you are interested in the aurora, do not look at Kp alone. Also check the current auroral oval, solar wind parameters, and how they change over time. Whether the aurora will actually be visible from a specific location also depends on conditions on Earth—primarily the time of day, cloud cover, light pollution, and visibility of the northern horizon.